US adventurer Steve Fossett has spent the past two decades chasing world records and shattering them, sailing, floating and flying faster and farther than anyone before.
A quiet man not given to emotional displays, Fossett has let his record-setting journeys and relentless determination speak for themselves.
But on Tuesday, a search was underway after a small plane Fossett was piloting went missing over Nevada, officials said.
Pushing his piloting skills and physical endurance to the outer limits, Fossett last year guided his Virgin Atlantic GlobalFlyer some 42,000 kilometers (26,000 miles) around the world despite a damaging gas leak at take-off and dangerous wind shifts.
By doing that the 63-year-old millionaire broke his own solo record, set in 2005 when he flew the same aircraft 36,898 kilometers (23,000 miles) around the world.
Last year he touched his aircraft down at an airfield on Britain's south coast, setting the record for the longest solo, non-stop, non-refueled flight in terms of distance.
After making a fortune on the turbulent floor of the Chicago Board Options Exchange, Fossett has set dozens of world records in sailboats, gliders and hot-air balloons.
A tireless athlete, Fossett has also swum the English Channel, raced in the Ironman Triathlon and taken part in the grueling 1,165 mile (1,887-kilometer) Iditarod Dogsled Race across Alaska. He competed in the 24-hour Le Mans auto race as well.
Fossett has set more than 100 world records in five sports, of which 62 remain unbroken, and he told AFP in 2005 that he had planned to carry on.
"There's no reason to stop," he said. "What I do will change -- when I'm 90 years old I can imagine sending a remote-controlled airplane around the world."
Fossett's modest manner belies the passion that fuels his costly and dangerous exploits.
"Frankly, I do them for the satisfaction of those achievements," Fossett has said. "I have a feeling of contentment and a satisfaction that I've done something faster or farther than anyone before."
He has survived numerous near-misses and harrowing crash landings over the years, including a 29,000-foot (9,000-meter) plummet into the Coral Sea off Australia because of a storm-shredded balloon.
Fossett shunned the media spotlight in the first years of his exploits. His motives were personal, he said, and he had no interest in making appearances or going on book tours.
In recent years, however, he realized that publicizing his adventures could be a public service and help to inspire new generations of adventurers. His website touts an autobiography due out soon.
Fossett has retired from his work as a stockbroker and investment consultant and devotes himself full-time to his thrill-seeking adventures in sailing, skiing, ballooning, gliding and jet airplanes.
Widely considered the world's most accomplished speed sailor, Fossett gained international fame in 2002 when he made it around the world on his sixth attempt at a solo balloon trip.
Since then, he has bested the world record for around-the-world sailing by six days and has set 10 of the 21 Glider Open World Records. He also holds 13 of the 22 Outright World Records as recognized by the World Sailing Speed Record Council.
Born in California, Fossett attended Stanford University before obtaining an MBA from Washington University in St. Louis. When he is not traveling for another record-breaking attempt, Fossett splits his time between homes in Colorado and California.
Fossett has received numerous awards for his exploits, including the Gold Air Medal from the Federation Aeronautique Internationale, the US Sailing Association's 2001 Yachtsman of the Year and a Distinction in Exploration from the National Geographic Society.