If you've never heard of Sheck Exley, you probably haven't spent much time diving in caves. Because when it came to cave diving, Exley was The Man. Even now, more than ten years after his death, his accomplishments seem almost superhuman.

The title of the book, though apropos, is taken from the classic poem Kubla Khan. Caverns opens with Exley's introduction to Florida's underwater caves during a Boy Scout trip to Silver Springs in the late 1950s. Armed with a mask and a pair of pins, he poked his head underwater, saw the opening to a cave, and was never quite able to pull his head back out again.

Exley went on to survive the 1960s, the early days of Florida caving when divers who became trapped in inside were drowning in record numbers. From there, Exley began exploring Blue Holes of the Bahamas, making solo dives in excess of 500 feet in Mexican caves, and going even farther by himself into obscenely deep caves in South Africa. Along the way, he experimented with mixed gasses, becoming one of the pioneers of tech diving, while also experiencing numerous mind-altering incidents of High Pressure Nervous Syndrome.

Obviously, Exley's final cave dive, on which he drowned at depth in excess of 900 feet,

isn't covered in Caverns. He wasn't around to write about it. He wrote about everything else, though. Never have I read a more dive-intensive book. If it doesn't pertain 100% to diving, it's not here. So much so that, after a while, it actually gets a bit repetitious -- one mind-blowing dive after another. But that's no reason to not read Caverns. Exley was an incredible guy and it's staggering to read the things he did. I recommend this book.

For a shorter account of his exploits and of the birth of tech diving that I wrote for Wired Magazine a few years back, click here.

Caverns Measureless to Man was published in 1994 by Cave Books.

Jerry Shine