The former senior music critic for The New York Times details the career of legendary pianist Vladimir Horowitz (1902-89), who has been the subject of a previous biography (Glenn Plaskin's Horowitz, 1983) as well as of a volume of personal memoirs (David Dubal's Evenings with Horowitz, 1991--not reviewed). Starting with Horowitz's triumphant return to Russia in 1986, Schonberg (The Glorious Ones, 1985, etc.) chronicles the life and music-making of this ""neurotic genius,"" drawing extensively on interviews with Horowitz and his associates. The author establishes appropriate historical and cultural contexts: Horowitz's youth during the Russian Revolution; the start of his European career in mid-1920's Berlin (which Schonherg calls ""a sad, bad, glad, mad city""); and his pianism as compared to that of the 19th-century romantics like Liszt and Anton Rubinstein, as well as to that of his contemporaries. Schonberg also considers changing musical tastes as reflected in varying critical perceptions of Horowitz's style during his lengthy career. Periodically, the author corroborates or disagrees with others' assessments--an intrusion, sometimes, in the text proper, but an asset in the three musicological appendices that preface an extensive Horowitz discography. Schonberg offers insight into the mutually dependent relationship between Horowitz and his wife, Wanda (Arturo Toscanini's daughter), but tends to apologize when accounting for Horowitz's four hiatuses from the concert stage. The author also tempers his subject's opinions on other musicians (e.g., Arthur Rubinstein) by choosing his quotes with kindness. Discussions of Horowitz's peculiar piano techniques (playing with flat instead of rounded fingers, for example) will interest piano devotees, although frequent documentation of individual concert programs proves cumbersome. Reasonably evenhanded, and useful in demythologizing Horowitz's career, but doing little to humanize ""the most potent and electrifying virtuoso of the twentieth century.