The Way of the Explorer: An Apollo Astronaut's Journey Through the Material and Mystical Worlds

The Way of the Explorer (Putnam, 1996) is the memoir and philosophy of Edgar Mitchell, the Apollo 14 lunar module pilot and sixth man to walk on the Moon. On the flight home in February 1971 he had what he called an overwhelming sense of universal connectedness, the conviction that the cosmos was in some way conscious. The book describes that experience and the work it led to: he left NASA, founded the Institute of Noetic Sciences in 1973, and spent the following decades studying consciousness, proposing what he called a "dyadic" model of reality.

It is not a UFO book, though Mitchell became one of the best-known voices on the subject in the same years, saying on Dateline NBC in 1996 that the evidence for alien contact was strong and classified, and in 2008 that Roswell was real. He also said, in 2014, that he had never seen a UFO himself and that his statements about a cover-up rested on what others had told him and on his own speculation.

Sources: Wikipedia · Open Library · Edgar Mitchell's file