Whatever the definitive critical biography of John Ford, arguably America's greatest poet/filmmaker, may prove to be, this isn't it; but it is a thorough, fluently written attempt that lacks the startling insight. The conundrum of Ford the man--heavy drinker, loyal spouse, cruel prankster, patriot, humanist, Catholic, naval spy, Democrat, Nixonite--may resist interpretation; and, where his work is concerned, the tale and not the teller is to be trusted, as many an earlier critic (Lindsay Anderson, Peter Bogdanovich, Joseph McBride, and most recently Andrew Sarris) has discovered. Sinclair is fine on Ford's Irish heritage and on his ""other"" naval career, but usually he's on firmest ground tackling the films (and weakest when he draws strained analogies between, for instance, the filmmaker's poor insight and inner vision). Fortunately, most of the book is film analysis, and though Sinclair goes overboard at times (Ford's shot of the raising of the flag on Midway is ""the synthesis of his life"") and underestimates such films as Seven Women and How Green Was My Valley, his judgment is generally sound and always clearly expressed. Ford's favorite antitheses, says Sinclair, are ""home against army, privilege against duty, private good against public order, mercy against the law""; his chief flaw as a filmmaker was evident ""on the rare occasion when his religious faith overcame his cinematic sense"": tenable arguments, as is the author's assertion that Ireland and New England were both vital influences on Ford's art. Sinclair, a novelist and biographer, also provides crisp, interesting plot descriptions--a rare asset in a book of this sort. What is missing is the passion for Ford the unique film director that is compelling in the criticism of Anderson and Bogdanovich and particularly in Andrew Sarris' much more uneven but often acute 1975 The John Ford Movie Mystery.