Mr. Tolischus, New York Times correspondent, was expelled from Germany for his best-selling They Wanted War. The news that he was a prisoner of the Japanese following the Pearl Harbor attack made his readers confident that he would have a book -- perhaps the book -- on Japan, a dissection with skilled scalpel, of the vicious source of Pacific holocaust. This is that book. It is not a book which bids for quick popular sale -- nor is it likely to get it. It is a scholar's book, as searching and penetrating in its way, and broader in scope, than Byas' Government by Assassination. There is a substantial amount of history, an analysis of social, economic, religious, political factors, and a day by day record of the mood, the tempo, the perversions of Japanese press, diplomacy and build-up for war. His own experiences, first as correspondent, then as prisoner, while interesting are perhaps, of secondary importance.