Once Is Not Enough is the third novel by Jacqueline Susann, published in 1973 following her huge bestsellers Valley of the Dolls (1966) and The Love Machine (1969). With Once Is Not Enough, Susann became the first writer in publishing history to have three consecutive #1 novels on the New York Times Best Seller list.

It is a world of money and spiritual incest, of drugs and frontal nudity, in a complex story which reflects the social upheavals of the late 1960s and early 1970s.