The failure of the Western governments and the League of Nations even to slap Japan's hand in 1931-32 as she grabbed Manchuria has often been viewed as the first prewar crisis of ""appeasement,"" a word Thorne avoids in this vast study of the incident. Thorne's vigorously pursued argument is that sanctions wouldn't have worked in any event; moreover, the crisis might have exposed the League's weakness but non-action did not cause it any more than it was responsible for the subsequent aggression of Japan and Germany. On this negative score the book is convincing. There is also a positive account of how policy was made in London, Paris and Washington. To Thorne's credit, his lengthy diplomatic narratives are rarely dull, and the characterization of officials -- the pillowy Sir John Simon, the austere Stimson -- are often acute. Britain and the U.S. arrived at a common policy of tolerating Japan's move, says Thorne, because opposition seemed dangerous to the British and unnecessary to the Americans; among the latter, however, there were general policy disputes over the Far East, with isolationism by no means a weak contender. In such a lengthy study one would have hoped for a deeper examination of the basic stakes; Thorne simply states that the West had little immediate material interest in the Manchurian business, but the background of Anglo-Japanese trade relations in particular remains shadowy, and the uninformed reader might be puzzled over Britain's pro-Japanese bias. The book questions the traditional view that long-term perspectives were lacking in the Western chambers of state during this period, but the impression of pragmatic stumbling and cynicism toward the League remains. Thorne, a Briton, is particularly detailed on Whitehall matters, but his chronicle of developments in Washington, and of the crisis as a whole, will engage specialists in the history of American Far Eastern policy.