At first it seems possible that these memoirs of theater/night-club superstar ""Dilys"" are meant as parody: a sendup of all those badly ghost-written, heart-on-sleeve showbiz autobiographies. Unfortunately, however, it soon becomes clear that first-novelist Grossman means for all the maudlin cliches and forced frolics here to be taken seriously. Dilys--""the five foot, three inch, eighty-three pound, blonde bombshell who sang better than Streisand and made Joan Rivers look like a tragedienne""--is now 40-ish, in a career slump, when a People-like magazine editor expresses interest in a comeback feature-interview. So, while chatting noisily with editor Amy, Dilys (nÃ‰e Diana Kramer) recalls her whole life story. Her young stardom in a B'way revival of The Boys from Syracuse. Her platonic paiship with soap-opera actor Carl. Her great nightclub act. Her great hit single (it ""did for me what 'Happy Days Are Here Again' did for Streisand""). Her recurring problems with overeating. Her problems with love--from an unpassionate affair with director Allie Goldman to would-be gigolo Tex to a life-long crush on British actor Nigel, who turns out to be . . . homosexual, of course. (""What a fool I'd been. What a colossal, grade A mutton-head!"") And, always in the background: her rivalry with long-estranged sister Cammie, a concert pianist who turns out to be . . . Dilys' most devoted fan/friend, of course--so it's Cammie (with a couple of old, old chums) who rallies 'round when Dilys is finally driven to a suicide-attempt. (The magazine article emerges as a hatchet-job.) Too unsensational and chatty to work as soap-opera, too flatly predictable to provide comic diversion: a bland paste-up for showbiz addicts only, then--and even they may find the details of Dilys' career lacking in both edge and authenticity.