Warren, a Canadian science journalist, combines the rigorous self-experimentation of Steven Johnson's Mind Wide Open with the wacky self-experimentation of A.J. Jacobs's The Know-It-All in this entertaining field guide to the varying levels of mental awareness. Beginning with the mild hallucinogenic state that comes just before true sleep, he tries to hone his skills at lucid dreaming, subjects himself to hypnosis and joins a Buddhist meditation retreat, among other adventures. Along the way, he begins to realize that dreaming and waking are equivalent states, and that we can learn how to induce the subtle gradations of consciousness within ourselves. This could come off as New Age psychobabble, but Warren is well versed in the scientific literature, and he provides detailed accounts of his own research. (During one three-week period, for example, he goes to bed at sundown to recreate a period of wakefulness before returning to sleep that used to be common before electric light reconfigured our sleep schedules.) His self-mocking attitude toward his inability to achieve instant nirvana, along with a steady stream of cartoon illustrations, ensures that his ideas remain accessible. More important than the theories, though, may be the basic tools—and the visionary spirit—that Warren hands off to those interested in hacking their own minds.