Mark Twight is an American climber, writer and the founder of Gym Jones. He rose to prominence as a mountaineer in the late 1980s and early 1990s with a series of difficult, dangerous alpine climbs in various ranges around the world. His radical, light-weight approach to alpinism has seen him regarded as an influential figure in the single-push movement.

Twight made first ascents on five continents, visited the Himalayas seven times, climbed icebergs floating off the Antarctic coast and spent five years living and climbing in the French Alps. His first ascent of "The Reality Bath" on the White Pyramid with Randy Rackliff remains unrepeated. He climbed professionally for fifteen years and then retired in 2000. After leaving climbing, Twight took up photography and competitive pistol shooting and competed in ski mountaineering and biking races.

Twight is the founder of Gym Jones, a private strength and conditioning facility, where he trains athletes including MMA fighters, NFL players and professional cyclists, military personnel, actors and others. His credits include, "Man of Steel", "300: Rise of an Empire", "Batman vs. Superman", "Wonder Woman" and "Justice League". He also consults as the technical director of Mountain Mobility Group, LLC, which provides "cold weather, high altitude, and fitness training, as well as R&D for the Department of Defense." He was hired as the subject matter expert during the development of the Protective Combat Uniform currently issued to special operations personnel.

He also is the author of "Extreme Alpinism: Climbing Light, Fast and High" which won the National Outdoor Book Award and the Mountain Exposition prize at the Banff Mountain Book Festival. When asked to describe it, he called it a “How Not To” book because the best lessons in it came from trial, error and failure that I and my partners eventually turned into success. He also authored an essay collection titled “Kiss or Kill -- Confessions of a Serial Climber". The book won the Mountain Literature prize at the Festival Banff and was short-listed at the Trento Mountain Book Festival in Italy. Kiss or Kill is available in Italian, Spanish, German, Polish, and Slovenian.

Awards: Recipient: American Alpine Club Underhill Award, 2017, Winner: Mountain Literature category, 2001 Banff Mountain Book Festival, Winner: 1999 National Outdoor Book Award, Shortlisted: Trento Mountain Book Festival 2005, Champion: Utah State IPSC (Stock, C class), 2000

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