Every Frankfurter biographer has had to deal with the paradox--the so-called ""enigma"" of the title--of his championship of Sacco-and-Vanzetti and other liberal causes as a Harvard law professor (1919-39), his commitment to judicial restraint as a Supreme Court Justice (1939-62). But, as has come to be recognized, Frankfurter took up civil-liberties causes because he perceived a miscarriage of justice, not out of sympathy with the defendants or what they stood for. If he was not, then, a liberal who turned conservative, it remains true that his intransigence vis-Ã -vis activist justices Black and Douglas was extreme--and for this obduracy and contentiousness, Hirsch (Government, Harvard) offers a psychological explanation, based on a combination of Erikson's scheme of identity formation and Horney's model of neurosis (with a dash of James David Barber and Daniel J. Levinson). Indeed, the whole point of this book is that Frankfurter represents ""a textbook case of a neurotic personality: someone whose self-image is overblown and yet. . . essential to his sense of well-being."" Though bright and personable, the argument goes, Frankfurter was small in stature and a Jew; hence his need for an ""idealized self-image""--which he acquired after a series of crises in 1916 (his father's death, the need to be responsible for his mother, fear of her opposition to his marriage to a non-Jew, the ugly to-do over Brandeis' Supreme Court nomination) and which, hard-won, he needed to maintain. His successes in the Twenties and Thirties--through defending one after another ""righteous cause against powerful opposition""--confirmed that self-image; but when he was appointed to the Supreme Court, he could no longer ""dominate every personal and professional situation in which he found himself""--and reacted by digging in and lashing out. Admittedly, Hirsch's presentation allows the reader to ponder other possible explanations. But it is, in itself, ludicrously reductive--a psychological strait-jacket with none of the subtlety or range of Erikson's psychobiographies of Luther and Gandhi. It compresses salient cases (e.g., Sacco and Vanzetti, the 1933 Securities Act) to the point of distortion; it omits countervailing evidence (especially re Frankfurter's Jewishness); it even seems, at times, to be contradicting itself. In no sense, certainly, is it a full, balanced account of Frankfurter's personal or public life--for which readers will still have to look to the works of Helen Shirley Thomas (1960) and Lira Baker (1969), and in particular to Joseph Lash's long biographical essay in From the Diaries of Felix Frankfurter (1975).