There is a decision you must make. The world is vast and unstructured. In it, things move seemingly at random. There comes a narrowing, a focusing, as the aperture reduces and reduces. The act, combined with training and skill and vision and, yes, philosophy, leads to a gradual, noiseless ratcheting down and down, like ripples in a pond going backward toward the pebble, closer and closer, smaller and smaller, the chaos dissipating into a tiny center of detailed clarity. And then the trigger.

Scott Tyler has been out of the Navy Seals for two years, but you don't simply forget what you did best. And what he did best, other than lead men in high-stakes combat, was aim a high-caliber, long-range rifle at a "target," be that machine, structure, or, most relevantly, a man, and, in Tyler's words, "take it out." That is what snipers do. Their craft – a part of warfare since the emergence of the Kentucky rifle during the American Revolution and in some ways even further back, to whenever the first accurate, long-distance bow shooter or rock thrower appeared – might seem outdated in an era of smart bombs and computer-controlled drones. But that is not the case. In the mountains of Afghanistan and the streets of Iraq, where the sporadically appearing plainclothes enemy might be far away, amid protective rocks, or close-up amid innocent citizens, stealth killing and accurate killing – the sniper's trademarks – are essential.

To shoot a man from a distance is a fascinating, awe-inspiring thing. It is nearly mythic in its godlike bequeathal of power. You are here, and he is there, and the connective and intensely private embrace is one of death. The two parties are linked by the flight of a tiny projectile traveling at supersonic speed, arriving to do its work well before the sound does and a moment after the powder flash and smoke are visible. To see that brief flash and to recognize, if only for a millisecond, that you will be the recipient of the explosive message, after which you will cease to exist, must be among the more horrifying recognitions there is. If the chamber noise is reduced and the blast light dulled (Tyler and the men he directed in Iraq, Afghanistan, and the Philippines generally used silencers or suppressors on the barrels of their rifles), the impact – a far-off head exploding, an arm abruptly detached, a body suddenly pierced by an invisible drill – occurs in a world without context or reason for the enemy, and is therefore not just terrifying but dispiriting.

"Long-range target interdiction: That's the two-dollar phrase," says Tyler, who sometimes speaks so quietly that you find yourself studying his lips. "In a conventional war you're on the battlefield, and if you look over and your buddy's head blows up and then you see another friend go down, it freaks you out. It demoralizes you; it makes you question things. It's a psychological thing. You, as a sniper, try for the highest-ranking person, if you can, to create that chaos. But in an insurgency, as we have now, when the enemy comes out in ones and twos, sometimes right in the cities, without ever being a big force, it's all ambush. So it can be better to have snipers rather than a man on every corner. A sniper team can stay hidden.''

Tyler now works when he can as a security consultant – a job that still takes him to hot spots such as Somalia and Iraq. His company, Qaletaqa Corps, works with various governments, tracking down terrorists and war criminals, and with private companies, planning logistics for their personnel traveling to volatile regions, sometimes even accompanying them. He was also recently featured in a short-lived reality show on NBC called 'The Wanted.' In that show, Tyler and three other specialists tracked down alleged terrorists and killers now living freely in other countries. Instead of a rifle, Tyler carried a passport and a camera. The trouble with the show was it made no final sense. The evildoers had found legal loopholes so they could live openly, and Tyler sure as hell couldn't go to, for instance, Norway, where the first episode occurred, and blast a dude from half a mile away. Though that would have been something.

At 5-foot-11, 185 pounds, Tyler is modestly sized, if muscular, with thick blacksmith hands, dark hair showing flecks of gray, and green eyes, one of which – the left – bears a birthmark that sometimes lends that iris a golden hue. Maybe the defect is actually a gift, because Tyler has 20/20 vision in his right eye but 20/15 in the left.

That's not the only unusual thing about Tyler, 36, a man who likes to meditate and contemplate big philosophical issues, such as the meaning of life. "People expect him to be so macho,'' says his mother, Kate, a former hippie who made jewelry and traveled about with her son in a lime-green school bus in southern California before settling down with second husband Darrol Rice in Rio Linda. "They expect that of a sniper. But he's so thoughtful, so open to suggestions, so concerned about others. When he was a little boy, he found five dollars on the playground, and he turned it in. When he went to sign up for the Marines, I thought we were going to the mall so he could hit me up for comic books."

He was 18 then, in 1991, coming off a restless high school career. (He was kicked out after spending more time surfing than studying, but eventually earned his GED.) He served a tour in Somalia, got out in 1996, and enrolled at the University of California–Berkeley. The elite, famously liberal school wasn't exactly clamoring for a surfer-dropout-turned–G.I. Joe, but Tyler cajoled military officials into writing him letters of recommendation. He settled on chemistry as his major, "because chemistry had kicked my ass'' in some early classes there, and he wasn't backing down from it again. After a year he had a 3.8 GPA, but his view of life from the chemistry lab was not fulfilling.

He had had a dream: He would continue on to medical school, become a doctor, and, rifle hanging in the back of his truck, work on an Indian reservation, where he would save lives while hiking into the roughest terrain. "I wanted to help people," he says. "But I was managing an apartment building and spending 80 to 90 hours a week studying. For what? So I could spend 80 to 90 hours a week studying in med school? I wanted to learn – knowledge for knowledge's sake – but it was all so competitive for no reason, so full of backstabbing, just a meat grinder. I looked out the windows of the lab, and there were the hills. And I knew I wanted to be back around people I liked being around."

So he switched his major to cognitive science – "why we think what we think," he says – and began hanging out with professors, "talking and trying to learn from them." One afternoon, Tyler and I visit his favorite professor at Berkeley, a cheerful man named John Matsui, the head of the scholars program in the department of integrative biology. As we sit in the campus coffee shop, Matsui says with something like awe, "I never had a student like Scott before. I knew you were intelligent. I saw that you would never quit. Your story was… different. Coming to school the way you did. Your desire to learn."

Even so, after he graduated in 2000, Tyler had had enough of school, and he felt himself drawn back to the military, but this time in more of a thinking role. He joined the navy to become a SEAL, one of those supersoldiers trained not only to fight on sea, on land, or in the air, but also to operate more independently. "I wanted to work in as small a unit as possible," he says. "I wanted to take all my determination, intentions, and skill and deliver it as precisely as I could – on the tip of a single bullet."

And that is how a sniper was born.

Part of being a great sniper is having the ability, the mind-set, to blend in, to disguise oneself, to become part of the landscape, to feel and react like soil, like leaves blowing in the wind. In The Ultimate Sniper, a technical guide for advanced snipers that Tyler references again and again, there is a section on Ghillie suits, the camouflage outfits that are designed to resemble the surrounding landscape. "A properly made Ghillie suit so well conceals the wearer that it never fails to impress first-time viewers,'' writes the author, retired army special forces major John L. Plaster. At sniper school, when an instructor talks about the suits, the point is reinforced when, after a spell, an innocuous part of the ground in front of the recruits slowly rises up and becomes human.

"The most important thing about a Ghillie suit is that you can attach other things to it," says Tyler. "It has loops everywhere, and you gather whatever's in your environment – leaves and grass and branches – and tape or string or zip-tie them on. It's a layman's myth that you cover yourself with burlap and you look like Chewbacca and that's that."

Snipers, whenever possible, work as two-man teams – one man spotting with a powerful scope, another shooting. But often even harder than shooting is the act of getting within range. It consists of patience almost beyond belief. There is the high crawl, the elbow crawl, the low crawl, and the sniper crawl. "The sniper crawl is the lowest, slowest movement technique…" Plaster writes, "used when movement must be so slow that there is no visible action to detect. [The sniper] creeps along, only four inches per move, using just fingers and toes to propel himself." With a rifle, of course.

Then come the difficult decisions. "I liked the cut-and-dry, liked it if a guy had a gun and was shooting at our troops, and we shot him," says Tyler. "It's a situation of less ambivalence. Nobody wants to go out and murder someone. You don't shoot just because you can. You have the trigger depressed and there is that final quarter-pound of pressure, and if you make a bad call.… Well, a 'bad kill' can create more insurgents, bad feelings, an international incident. But the biggest thing is, you have to live with it.''

Tyler has won two bronze stars for valor. The first one stemmed from a 2003 incident in which his sniper team was providing support for a unit taking down a Taliban stronghold in the Afghanistan mountains. "We got into a combat situation and had to shoot our way through it," says Tyler, reluctant to say more. It's the second bronze star, though, that illustrates how gray the decision making in the field can get. That one came after a 2005 firefight in the Philippines, where he and other U.S. soldiers had been sent to assist the government in hunting down extremists. The document that accompanied that award notes that Tyler "without regard for his own personal safety…led a two-man element to rescue four injured personnel." The truth is that Tyler came damned close to disobeying orders, since he was supposed to be an "observer," not a combatant. He and another SEAL used two small boats to go up a river, firing all the way, to pull out ambushed and wounded Filipino troops. It was political dynamite, but human grace. Tyler could have been court-martialed as easily as decorated.

"The men had been shot up; they were bleeding out," he says. "I got on the phone with the captain back at the base, and he wanted us to wait. He didn't want to make the call, politically. Then my phone fell in the water. It kind of slipped out of my hand. Even now I don't know if I did it on purpose." Three of the four men he rescued survived, and Scott Tyler's reputation spread.

The men in his platoons revered him, because he was meticulous, because he was loyal and smart, because he followed the rules but still thought philosophically and creatively. "I love the guy like a brother," says Dave Hansen, a 13-year SEAL chief petty officer who served under Tyler in Iraq in 2005. "He constantly thought outside the box. Need something done? Just give him the facts and leave him alone. Because he was so good at so many things, he was always able to get us into combat, which is the point. I mean, there he is, knee-deep in craziness, smoking a lot of dudes, and doing it the right way. Mr. Rice" – Tyler recently changed his name from Rice back to Tyler, his birth name, as a way of reconnecting with his birth dad, but many of his fellow former soldiers still call him that – "he is the kind of guy who's gonna save your ass. Maybe that's what comes through in his art.''

Oh yes, the art. Tyler is a sculptor; he learned welding from his birth father and has created some remarkably beautiful and thought-provoking moving sculptures out of stainless steel and stone. We visit a gallery in Stinson Beach where one of his pieces, Spatial Relationships, is on display in the yard, and the slightest breeze sets arms on the heavy, earth-toned metal-and-rock form into improbable, silent, delicate motion. "My art has to do with the positive spaces and negative spaces of a landscape,'' Tyler explains. "That goes with the art of being a sniper. A person's instinct, your eye, will go from positive space – a tree, a rock – to positive space. Negative space is the space in between. Deer and coyotes have the ability, with their coloring, to stand still in negative space, to hide in plain sight. Our eye notices straight lines, perfect circles, shiny things in the wild because they're out of place. Those are not natural forms or shapes. I like things that blend into the landscape. I find nothing more beautiful than trees and rocks.''

Scott Tyler was in a stone hut in Iraq's Amdar province, east of Ramadi. This was in 2005, and the wrecked little building, about 10 feet by 12 feet, had been dubbed "the hot dog stand" by members of the SEAL team who occasionally used it for cover in the no-man's-land of destruction. Tyler was with two men from his sniper team, observing the gray ambivalent scene outside, when they noticed a suspicious-looking local man checking out places where the SEALs sometimes set up. The man studied the road the military used regularly. He had on a robe, and it was impossible to see what he might be carrying underneath. The man looked at the hut. He walked closer and stared into the opening about five feet off the ground, at eye level, the place where the SEALs had built an observation deck out of bricks inside the hot dog stand. The man stared directly at Tyler, from six feet away, into his face.

Tyler was covered with his own handmade camouflage suit, spray-painted different colors "like a chameleon," with a mottled front he had designed "not to look like a human, but to be natural and exist in negative space, to be invisible." He had layers of mosquito netting covering his face, and he had backed into the shadows. The man could not see Tyler, could not even see his green eyes.

"Every hair on my body was standing on end,'' Tyler says. "He could have tossed a grenade into that opening. But I need to see that he is a threat, absolutely. I need to know. He has to deserve to die."

The man left and 20 minutes later returned with someone else. The first man began to dig a hole in the roadway with a trowel while the other served as a lookout. The first man dropped something into the hole, perhaps a bomb.

"I didn't have a rifle, but I confirmed the target – both of those guys – and I cleared my men hot. It would be a simultaneous shoot. I counted down – 'Three, two, one…' and we took out the mine guy, about 75 meters away, and the lookout guy, about 125 meters away, at the same time. We had to do it precisely so that neither would be alerted. Within seconds a truck came flying down the road and picked up the farther body. But the first guy had fallen directly on top of the mine, or whatever it was. And it was a mine. We detonated it, and he disappeared."

Tyler didn't take those death shots, but he produced them. Though he won't talk about it, it seems likely that snipers under his command have killed more than two dozen men, and he himself has killed maybe a half dozen or more. He won't deny that. And maybe the body count is much higher. He doesn't like to discuss it. "There are noncombatants in that number," he says.

"If I shot somebody, or men under my command did, I took full responsibility for that. I know that helped the men, lifted the burden." But what about the burden on him? "It sucks. It's impossible, really, trying to be precise. Nothing is clear. I never had a textbook case. Never. You do your best. You follow the rules of engagement, your conscience. And then the next morning you wake up and you think, Oh, my God."

At a shooting range outside Nevada City, far up in the wooded, mountainous eastern corner of California, not far from Reno, Tyler lies motionless on his belly in his khaki uniform, his heels pressed flat on the wooden platform, an Austrian-made Steyr Mannlicher .308 collector-grade sniper rifle pressed against his cheek. The rifle is brand-new and belongs to a range member named Rod. Next to Tyler is a box of Hornady 150-grain, lead-core, copper-jacketed, high-impact bullets with polymer tips. The tips are harder than the surrounding lead, so the synthetic red cone will be driven back on impact, causing a small explosion of lead fragments into the target, thus creating a larger hole at the back of a man than at the front. These bullets will travel more than half a mile per second.

Each rifle a sniper uses has unique characteristics that are compounded by the ammunition and many, many exterior factors. There is wind. There is humidity. There is the spin of the Earth. There is even the fact that as a rifle is fired, its barrel heats up, the metal contracts, and the bullets are propelled faster. As a sniper Tyler had a "quiver of rifles," including a huge .50-caliber McMillan Brothers bolt-action, a .300 Winmag, and an MK 12, which he liked because it was light and small, though it "didn't pack much of a punch" in the recoil. But his favorite was a CheyTac .408, a weapon he discovered late in his career and never used on a human. "It was accurate up to 2,500 yards," he says. "The round had a very stable flight. Most rounds, when they go from supersonic to subsonic, start to tumble. This one tumbles and then restabilizes."

I ask Tyler about the drama shots we see from snipers in the movies, like how they always seem to be shooting one another through their scopes. "It's mostly Hollywood," he says. "Head shots seldom happen. Anywhere from here to here" – he indicates the lower chest to the neck – "is good. There are so many variables. A shot that's off by an inch at 100 yards will be off by 10 inches or more at a thousand yards."

To ensure he's as accurate as possible, Tyler meticulously charts the results from his practice shooting, logging all the variances he can think of – temperature, barometric pressure, wind speed, direction. He's looking for patterns – not just, say, how one type of bullet might vary from another, but how one particular batch of that bullet might vary. "That way when it comes down to game time you know what's going to happen," he says.

In combat Tyler never took a shot from more than 400 yards. But at a practice range in Idaho, he once hit a foot-square metal target from 1,600 yards. He was shooting across a valley, amid a furious wind and rain, and still hit the target on his first try. "We used the ballistic computers to deal with the environmental conditions," he says matter-of-factly. That bullet was in the air for well over a second, rising, spiraling, descending, and fading to the right like a Tom Brady Hail Mary pass.

As astonishing as that feat was, it doesn't come close to the long-distance killing record that was recently set by a Canadian sniper in Afghanistan. His fatal shot traveled 2,657 yards – more than a mile and a half. That bullet was in the air for four seconds and dropped 146 feet, while also curving to the side a good amount. "Those Canadians," Tyler says, "they're raising the bar pretty high."

The range is now silent, even though 15 men have come by from various spots, shuffling and eager, to see the SEAL shoot.

"Going hot,'' Tyler says.

He appears to have no breathing at all, no motion, no nothing. His feet are laid out flat on their sides behind him because snipers do not give the enemy even the sight of raised heels as targets.

There is an explosion, and then silence. He racks the bolt, and a bright, smoking casing pops out. He picks it up and lays it carefully to his right. He shoots again.

When he shoots, Tyler keeps both eyes open and lets the floating circular reticules hover like a halo around the target. "I try to get in a good pattern of breathing, try to relax everything. I'll pull the slack off the trigger and know I'm at the point where only the mechanism is barely keeping the hammer back. You do not slap the trigger. You have to be in the moment. It's a little bit of an out-of-body experience." High-powered rifles are incredibly loud. They can be deafening. But Tyler has shot in war zones without muffling devices or earplugs. And a strange thing happens. "I don't hear the blast,'' he says. "I don't hear anything."

He mentions that many hunters – regular guys out for deer, longhorn, elk – flinch at the last moment, because they're not relaxed. Because they're thinking of what they're doing. A sniper can do what he does because – after months and months of training and study and reflection – he knows that he has done it all before thousands of times, effortlessly. "It's like golf,'' Tyler says, "except every time you swing there's an explosion in your face."

This gun, a gun he never used before, misfires three times on the range, and the scope has never been accurately adjusted, but when we walk the 218 yards – two football fields, two end zones – to the target, the Styrofoam square has three patterns of three holes, each of which could be covered by a quarter.

It's worth noting that Tyler does not especially like guns. He owns only a shotgun, which he has never shot and which he needed when he lived up in the hills of the Sierras with his wife and young daughter (he is recently divorced) as protection from meandering bears. He has never hunted, never killed an animal, never even shot at an animal.

Hemingway once wrote: "Certainly there is no hunting like the hunting of man and those who have hunted armed men long enough and liked it, never really care for anything else thereafter." But that is not strictly the case for Tyler. He left the service voluntarily, because he felt his principles were being violated by a superior's decisions. It had to do with responsibility – his for the men under him. And he could not live with his conscience.

He admits he is still searching now, trying to come up with a lifestyle that embraces all that he is, all that he has done. Without a permanent address, he's basically living in his pickup truck. He's dating, and he wants to marry again, have more children, continue his art, and live "in a Mongolian yurt along the Pacific coast."

A nice vision. But it must coexist with Tyler's memory of, for instance, the first time he was fired upon in Baghdad: "We were in the back of a Humvee and I thought it was cigarette ashes flicked from a car. Heard nothing, had no idea where it was coming from. Just sparks skipping across stones." The man riding next to Tyler said, "Motherfucker! The turret guy just hit me in the back of the head with the turret!" But the turret was high up. He'd been shot in the neck. By a sniper.

A man, a thinking man, a philosophical man, chooses to be a sniper, to fight his war from a distance. And why would he do so?

Maybe because he can say this, as Scott Tyler does: "If you're shooting from 700 yards, you become the scope, you go down it, you become the tip of the bullet, you project yourself 700 yards. You're there."