In 1966, a chance phone call from an old friend led Michael V. Palmer to San Francisco's Haight-Ashbury neighborhood, a place populated by hippies, musicians, psychics, and yogis. To Palmer's delight, many of his new friends dabbled in all of the above, and everyone wanted to spread the love. Much of that good feeling stemmed from a collective mental awakening inspired by a new controversial psychedelic concoction: LSD. For Palmer and his contemporaries,...