Smokejumper, by Jason Ramos, is the memoir of a man whose job responsibilities include: 1. Jumping from airplanes, 2. Into forest fires. The book’s title comes from the name of the profession: smokejumpers insert into remote, inaccessible areas of forests in order to stop forest fires from becoming catastrophic. Because their work is conducted in isolation, they carry everything they need to survive and control a blaze—over 100 pounds of gear in all. They train like commandos and parachute into hell on Earth. Here are 10 things the book reveals about the men and women who call themselves smokejumpers.

1. A small fire that went nova led to the creation of the smokejumper program.

In 1937, a fire in Shoshone National Forest, Wyo., burned for two days before being discovered. By then, it had grown by two orders of magnitude, and “eventually exploded into a firestorm,” claiming the lives of 15 firefighters and injuring 38 others. Accessing remote terrain was a problem for firefighters. Heavy equipment and vehicles couldn’t make the journey, and days might be lost attempting to get there on foot. The solution: parachute the men onto the scene and airdrop the equipment. In 1939, the U.S. Forest Service used surplus funding it had on hand to establish a test smokejumper program in Winthrow, Wash. The first fire jump was made the following year (just 37 years after the Wright Brothers invented the airplane, Ramos notes). By the end of that first active season, smokejumpers saved the government $30,000 on top of a $9047 investment. The program was considered a success, and was soon expanded.

2. The training is intense.

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Smokejumpers land adjacent to forest fires, on wild, forested, mountainous terrain. They train to successfully exit cargo planes (a bad exit means a bad parachute deployment); to land in the wilderness (on these types of low-altitude, static-line jumps, a parachutist is more like an asteroid than a skydiver); to climb down from the tall, unforgiving trees their parachutes are likely to snag; to secure their airdropped equipment; and, oh yeah, to fight a forest fire without the benefit of support. The foundation of all of this is peak physical fitness and the ability to scurry up steep mountains while carrying over 100 pounds of gear. You have to really want a job like that, and few have what it takes to pass the physical training.

3. They are the special ops of the firefighting world.

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Smokejumper teams are designated “Type 1,” as part of the national emergency response incident command system (ICS). Ramos writes that Type 1 means “biggest and baddest, whether you’re talking about resources like aircraft and vehicles (Type 1 are the largest) or personnel.” Members of Type 1 units “typically have the most training and experience.” Other elite firefighting units include “hotshots,” who work the most complex terrain in the nation, and helitack crews, who are transported by helicopter, and rappel down to the fires below.

4. The jump is the hard part.

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When the alert siren goes off, smokejumpers grab their gear and suit up. Each wears a jumpsuit with an outer layer that can resist cuts, punctures, and abrasions from trees and other hazards likely to be encountered during the final moments before landing. The suit is also fire-resistant, able to withstand 2000 degrees for 4 seconds. Padding is also sewn into the suit at strategic places. Beneath the jumpsuits are standard-issue fire gear. After pulling on their suits, gear, parachutes, and helmets, smokejumpers board a plane and take off.

From the air, smokejumpers receive jump commands to ensure equipment is properly rigged and that static lines are correctly attached from parachutes to the plane. (A static line is the equivalent of a ripcord; there are a couple of seconds’ worth of slack, and once a jumper exits the aircraft, the static line pulls the parachute from its pack. If a parachute doesn’t deploy, jumpers also wear a reserve chute that can be manually activated.) “Spotters” on the plane keep an eye out for the fire and make decisions as to when smokejumpers should make their exits. Once a suitable area is chosen, streamers are thrown from the plane to reveal wind speed and direction.

When the signal is given, smokejumpers exit the aircraft in tight body positions. They go airborne around 1500 feet, and hurtle from there toward the Earth. Chutes deploy (hopefully) and when the ground gets close, feet and knees are kept together, legs slightly bent. They are trained to hit the ground in a kind of roll that’s called a “parachute landing fall.” In the space of about a second, jumpers touch the ground with the balls of their feet, rolling in the direction of the landing, absorbing gravity with the calf, thigh, hips, and the side of the back.

5. The firefighting is also the hard part.

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On the ground, jumpers shed their jump gear and jump suits, link up, and secure their gear, which was airdropped in separate containers. The boxes sustain a smokejumper on location for at least 48 hours, and contain food, chainsaws, first aid kits, water, and so on. After a brief regrouping, they head toward the fire.

The general strategy is to first “build a line” from the fire’s point of origin, using a feature such as a road or stream, if available, or to dredge a line themselves, if necessary. A line keeps the fire from circling back. From the origin, and working toward the “head” of the fire (where it is spreading fastest), the smokejumpers flank the fire, suppressing it by cutting down fuel sources—everything from “scrubby bushes to hundred foot trees.” Eventually they extinguish the head “like fingers snuffing out a match.” This is grueling labor, involving handsaws and mountainous wilderness. And also giant walls of fire.

6. There have been a few famous smokejumpers.

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It’s hard to top “smokejumper” on a resume, but a few have managed. In May 1963, smokejumper and mountaineer Willi Unsoeld and mountaineer Tom Hornbein climbed the west ridge of Mt. Everest, pioneering a new, challenging route. In 1967, George Sisler from the North Cascades Smokejumper Base earned the Medal of Honor for actions during the Vietnam War. (He also once won the National Collegiate Skydiving Competition—with one leg in a cast.) Four years later, Stuart Roosa, a smokejumper from the Cave Junction, Ore. base, topped everyone by going to the moon as part of Apollo 14.

7. Smokejumpers inspired the creation of the 101st Airborne Division.

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In 1940, William C. Lee, a major in the U.S. Army, visited a smokejumper training camp in Montana. He was inspired by the training and by the military potential of smokejumper techniques. He went on to found the 101st Airborne Division of the U.S. Army. (His soldiers—and the procedures first explored by smokejumpers—were depicted in the series Band of Brothers.)

8. The CIA used smokejumpers during Vietnam.

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The Central Intelligence Agency recruited heavily from smokejumper ranks during the Vietnam War. As Ramos explains, the CIA “needed people who knew how to drop cargo from low-flying planes, accurately, in rough terrain, under urgent and less-than-ideal conditions.” More than 50 smokejumpers participated in covert actions in Laos, Vietnam, Thailand, and Cambodia. It was a poorly kept secret among jumpers: “There was a lot of wink-wink-nudge-nudge in the spring, when guys would come back from a season in ‘Alaska’ or ‘Maine’ with sunburns and jungle rot between their toes.” Nine smokejumpers died while working for the CIA.

9. Smokejumpers protected the U.S. during the Second World War.

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During World War II, the 555th Parachute Infantry Battalion, an all-black army airborne unit, was stationed on the West Coast of the United States to protect against an onslaught of “fire balloons” from Japan. Between 1944 and 1945, 9000 balloon-based incendiary devices were sent to the United States; 1000 made it to American shores. While on alert for balloon bombs, the 555th “made more than 1200 fire jumps and worked on 36 forest fires in the Pacific Northwest.” (One member of the 555th was killed on a fire jump.) As a result, in addition to helping protect the United States from being reduced to cinders, smokejumping became one of the first racially integrated jobs in America.

10. Smokejumpers are great at sewing.

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There are fewer than 500 smokejumpers working today (and fewer than 6000 ever). As a result, the gear they need can’t really be found at the local Walmart. “We have to make all our jumpsuits, harnesses, and gear bags ourselves, from scratch,” Ramos writes. “In my first few seasons, I learned that inspecting, repairing and making your own gear is a big part of daily life between fire jumps.” Designs are handed down from generation to generation of jumper, tweaked based on new technologies and experiences, and quality control is maintained by people who truly know the stakes.