At first, you may be disappointed that Auto da Fay, Fay Weldon's memoir, does not extend into the full maturity of her writing career, which has included corrosive comic novels such as 1984's ''The Life and Loves of a She-Devil'' and 1991's ''Darcy's Utopia.'' But soon you start reveling in her rocky New Zealand family history, her tart appraisal of an early career as an ad copywriter, and an even more tart appraisal of marriage: ''...what happens when one at least of the partners doesn't want the other to get away.'' Can't wait for the second volume.

