Much of Kim Stanley Robinson’s prodigious science fiction has ecological underpinnings—so it comes as no surprise that the oft-decorated writer has a real-life passion for wilderness. More specifically, Robinson loves the Sierra Nevada, the geological backbone of California, where he has lived most of his life. In The High Sierra, a capacious and truly original work of nonfiction, Robinson expresses his enduring appreciation for these mountains and the time he has spent there. A mashup of travelogue, geology lesson, hiking guide, history and meditation, all wrapped in a revealing and personal memoir (and illustrated with scores of gorgeous color photographs and illustrations), the book is, in essence, an exuberant celebration of finding purpose in nature.

The Hugo, Nebula and Locus Award-winning writer first visited the Sierra as a college student almost 50 years ago, and since then he has made more than a hundred return visits, spending untold hours in its eternal landscape. There have been group excursions and solo treks in every season. In his hippie days, he even enhanced the mountain high by dropping acid. Accounts of these experiences, sometimes risky, sometimes funny, but always deeply meaningful, give shape to Robinson’s larger narrative. The memories are intercut and augmented by chapters delineated by categories such as geology, Sierra people, routes and moments of being. These disparate chapters coalesce into a surprisingly seamless narrative that conveys the full measure of Robinson’s deep affection for the place and its past, as well as its significance to him personally.

Robinson’s writing is companionable and welcoming, never dry or preachy, as any field guide worth its salt should be. There is unconventional humor—he classifies place names as the good, the bad and the ugly, for instance, and his chapters on fish, frogs and bighorn sheep are all grouped under “Sierra People”—but cases of appalling human behaviors, past and present, are never glossed over.

Robinson introduces the usual suspects in the history of the Sierra—John Muir, Clarence King—but devotes equal attention to less familiar faces. He taps into the work of other Sierra-loving writers, too, including early feminist Mary Austin and the poet Gary Snyder, who is Robinson’s friend and mentor. He even shares some of his own youthful, heartfelt poetry, composed amid the elation of the mountain terrain.

Although Robinson’s mountaineering focus is the Sierra, he does take readers on brief forays into the Swiss Alps (including an account of his ascent of the Matterhorn). But The High Sierra should not be narrowly viewed as a book only for the die-hard outdoorsperson. Robinson’s greater project, at which he succeeds splendidly, is to share the magic of his personal happy place, to promote not only its admiration but also its preservation. When asked why this is a lifelong project of his, Robinson says there is no satisfactory answer, except to pose a question of his own: Why live?