Biography may be, as George Eliot once claimed, generally a British disease, but it is one which some Americans nonetheless contract and suffer gladly. Among its happiest victims, Gay Wilson Allen has distinguished himself as one of the foremost American practitioners of what Andre Maurois labeled "the Anglo-Saxon genre" of literary biography. Known internationally as the dean of Walt Whitman scholars, Allen has completed an acclaimed trilogy detailing the remarkable lives of three of America's most original and influential thinkers. The Solitary Singer (1955; revised 1967) remains the standard critical biography of Whitman; William James (1967) is acknowledged as the only true biography of that eminent psychologist and philosopher; and Waldo Emerson (1981) provides a long-needed account of its subject's personal and intellectual life. Allen has also trained his discerning scholarly eye on Herman Melville (1971), Carl Sandburg (1972), and St. John de Crevecoeur (1987); but it is for that trio of major life stories...