LSD inventor Albert Hofman called it "medicine for the soul." The Beatles wrote songs about it. Secret military mind control experiments sought to exploit its hallucinogenic powers. Outlawed in 1966, LSD became a street drug and developed a reputation as the dangerous toy of the counterculture, capable of inspiring either moments of genius or a descent into madness. Now science is taking a fresh look at LSD, including the first human trials in over 35 years. Fifty years ago, psychedelics like LSD were considered the cutting edge of science. After decades of controversy, LSD is being reconsidered by the research community – to enhance brainpower, expand our creativity and even cure disease. How did LSD go from being a lab accident to CIA secret weapon to psychedelic plaything?