In 1995, National Park Service Ranger Doug Thompson saw the Guadalupe Mountains of New Mexico and thought they were clouds. Little did he know, but for the next six years he would work under those clouds, and beneath those mountains at Carlsbad Caverns National Park. He was looking for a challenge after two decades as a ranger, and found one.

In Underground Ranger (University of New Mexico Press), Thompson’s memoir of his life as a cave ranger rings true, as only someone who has “been there-done that” could describe. The 272-page paperback book is perfect to stow in your pack for some insightful reading on your travels.

As an interpretive ranger, he would soon lead visitors deep underground into the wonderland of stalagmites, helictites, columns, and flowstone and explain how they were created. He also would overcome his fear of heights and confined spaces to explore many of the surrounding features, including the magnificent Lechuguilla Cave.

In this book, Thompson takes you along as he explains the methods to his cave obsession, from free-hanging rappels and tight spaces (including one called the Poop Chute), that grew as he explored more and more of this underground wilderness. There was wonder as he went places no human had ventured, and drama as he helped rescue stranded visitors as part of the park’s technical rescue team, a task that at times required him to drop more than 500 feet into the darkness.

This is a well-written book, with insights into the native culture’s connection to the underground, and the animals that lived above, and below, the surface: from the nightly flight of thousands of bats exiting Carlsbad Cave to a chance encounter (too close) with a cougar, and to salamanders that never saw the light.

Thompson’s love for the natural world, and this particular desert, shine through in these pages. I do wish, however, that he would describe vertical drops in feet, rather than saying a 100-foot pit was a ten-story drop. Perhaps for most visitors from urban areas that might be more relevant.

This is a personal book written as only an interpretive ranger could, with humor, humanity, and a humble outlook as he shares his passion. This desolate border country where New Mexico meets Texas isn’t for everyone, but those who spend even a little time in this desert will grow to love it, just as Ranger Doug has done.