"Turn on, tune in, drop out," Timothy Leary advised young people in the 1960s. And many did, creating a counterculture built on drugs, rock music, sexual liberation, and communal living. The hippies preached free love, promoted flower power, and cautioned against trusting anyone over thirty. Eschewing money, materialism, and politics, they repudiated the mainstream values of the times. Along the way, these counterculturists created a lasting legacy...