Jablonski, co-author of The Gershwin Years and veteran Gershwin authority, offers a valuable, up-to-date, yet not-quite-definitive George Gershwin biography--strong on the least familiar works, sketchy in some well-trod areas, and perhaps too timid (in contrast to the brashness of Charles Schwartz's 1973 bio) in considering the composer's personality and private life. The essential life-story here differs little from previous versions: from Lower East Side boyhood to piano studies and Tin Pan Alley song-plugging; from single-song successes (""Swanee"") to Broadway scores, Rhapsody in Blue, and 1920's super, celebrity; toward opera, from Of Thee I Sing to Porgy and Bess; to Hollywood for Fred Astaire films; and death at age 38 from an inoperable brain tumor. But, while some of Jablonski's sources are very familiar (Isaac Goldberg's 1931 bio, the late Ira Gershwin's Lyri'cs on Several Occasions), he also draws on privately-held letters, journals, and interviews--many supplied by Jablonski's longtime mentor Ira--for fresh details and perspectives. (The collaborative process that produced Porgy and Bess is thus given unusually full, vivid treatment.) Also noteworthy is the focus on underappreciated Gershwin compositions: Jablonski singles out virtually unknown songs that deserve rehearing; and he gives special attention to the Second Rhapsody--condemning (even more sharply than Schwartz did) its reorchestration after Gershwin's death. On the other hand, however, while providing extensive detail on Let 'Em Eat Cake, Jablonski's discussion of its famous predecessor, Of Thee I Sing, is surprisingly skimpy; similarly, the story behind Porgy and Bess is much more firmly described than the opera itself. And, partly because of Jablonski's dry, rarely evocative style, little sense of Gershwin's character emerges here; as for his love-life, Jablonski deemphasizes the libertine aspect, largely echoes previous biographers re George's infatuation with Paulette Goddard, expands a bit (to softening effect) on the relationship with Kay Swift, and concludes that ""he apparently did not want the kind of marriage that his parents endured."" Throughout, in fact, one senses that labionski's Gershwin-family ties may be con-straining of coloring his biographical approach. Still, notwithstanding this and other limitations, students and fans will welcome this solid, conscientious chronicle--which also includes a section on Ira's post-1937 career, a full list of songs and concert works, and a ""Selected Discography"" rich in critical commentary.