Whether you lived through the sixties and seventies or just wish you had, this revised and expanded edition of the Hippie Dictionary entertains as much as it educates. Cultural and political listings such as ''Age of Aquarius,'' ''Ceasar Chavez,'' and ''Black Power Movement,'' plus popular phrases like ''acid flashback,'' ''get a grip,'' and ''are you for real?'' will remind you of how revolutionary those 20 years were. Although the hippie era spans two decades beginning with the approval of the birth control pill in 1960 and ending with the death of John Lennon in 1980, it wasn't all about sex, drugs, and rock'n' roll. These were the early years of pro-ecology and anti-capitalist beliefs-beliefs that are just as timely as ever. So kick back and trip out on the new entries as well as the old, and discover why some are dubbing the sixties and seventies ''the intellectual renaissance of the 20th century.