Gary Joseph Lachman (born December 24, 1955), also known as Gary Valentine, is an American writer and musician. He came to prominence in the mid-1970s as the bass guitarist for rock band Blondie. Since the 1990s, Lachman has written full-time, often about mysticism and occultism. He has written more than 22 books on consciousness, culture, and the western esoteric tradition, written for journals in the US and UK, and lectured on his work in the US and Europe; his books have been translated into more than a dozen languages.