When a writer leads as externally undramatic a life as Thornton Wilder's--prep-school and college teaching, literary friendships, a little show-biz, a lot of travel--a biography that fails to illuminate the inner life will most likely become a dull, shallow, mechanical string of facts, plot summaries, and quotes. . . like this one. Though Simon (The Biography of Alice B. Toklas) has done solid research and has interviewed dozens of Wilder's friends and students, she finds no pattern or development in the long, even-tempered career: bookish son of an autocratic journalist/diplomat, Wilder grew up in China and California, studied at Oberlin and Yale and writer colonies, won sudden fame (and a Pulitzer) for Bridge of San Luis Rey, branched out into theater with Our Town and Skin of Our Teeth (both controversial), and slowly wound down to become the ""kindly granddad of American letters."" Simon describes each work--even lectures--and the critical reaction to it, but she brings no fresh perspectives to the canon, serving up the familiar Wilder catchwords: ""His faith was in people, in humankind. . . optimism and hope."" (Also, inadequate attention is paid to the early, ground-breaking one-act plays.) She details the surfaces of Wilder's friendships with Gertrude Stein and others, but the impact of these ties is never defined. And, as for Wilder's most private life, Simon very briefly labels him as homosexual but never relates this to either work or relationships (a glaring omission when the relationships involve Alexander Woollcott or Montgomery Clift); and she declines to investigate what appears (even in the sketchy references here) to have been a crucial, crippling family background. P. N. Furbank's biography of E. M. Forster demonstrated that a constricted, repressed life can be taut, richly textured drama; so Simon's limply written chronology-with-quotes--though it does turn up an oddity or two, like Wilder's taste in bawdy limericks--leaves open the possibility that a more probing, candid biographer might manage to put some flesh and blood on the stick-figure Wilder here.