Cernan's book The Last Man on the Moon (St. Martin's Press) is "very first-person," he says in an interview with space.com. Rather than focus on technology, he sought to explain what it felt like to be a member of the space program in the 1960s and 70s. That includes the dark side of such a life--the loneliness and worries of the astronauts' wives, for instance.

The book, published in April 1999, was co-authored with journalist Don Davis over a period of two and a half years. In seeking a collaborator, Cernan says, "I needed someone willing to not just delve into my mind but to dive into my heart and soul."

Cernan went into space three times. He served as commander of Apollo 17, the final manned moon mission, and participated in the Gemini 9 and Apollo 10 missions.

The book has gotten compliments from his fellow astronauts, says Cernan. "I grew up in the space program with some of the most competitive guys around. And when you get congratulation from your peers--when these guys tell you "hey, you've done a great job'--then you know you've arrived."