David Roberts, the mountain climber and prolific author whose books are widely considered modern classics of adventure writing, has died at 78, the New York Times reports. The cause of death was emphysema.

Roberts, a Denver native, took to mountains early. As a high school student, he climbed peaks near Boulder, Colorado, and as a Harvard student, he led the university’s mountaineering club, which would take him to the wilds of Alaska.

In 1968, he published The Mountain of My Fear, which told the story of a climbing expedition in Alaska that led to the death of one of his friends. Two years later, Deborah: A Wilderness Narrative was published; both books are still widely read among mountaineering enthusiasts.

Thirty other books would follow, including True Summit, Devil’s Gate, and, most recently, The Bears Ears, which was published by W.W. Norton in February.

Roberts’ admirers paid tribute to him on social media. On Twitter, journalist Ash Routen wrote, “A huge loss to the adventure community, with the passing of David Roberts the ‘dean of adventure writing’. One of his books had a big influence on me and I’m glad I wrote to him last year to tell him that. Vale David Roberts.”

And novelist Meg Gardiner tweeted, “Farewell to the amazing writer David Roberts. I read ON THE RIDGE BETWEEN LIFE AND DEATH as research, and came away so moved by its power that I read as much of Roberts' writing as I could get my hands on. RIP.”

Michael Schaub is a Texas-based journalist and regular contributor to NPR.