Who knew about 'final solution'?; The Terrible Secret, by Walter Lacqueur. Boston: Little, Brown & Co. $12.95.

Other than for the course of communism, no other phenomenon of the 20th century has so caught the attention of thoughtful individuals as has Nazism. Hitler, his philosophy, and his works have raised innumerable intellectual, moral, social, psychological, historical, and even racial questions. As has been said, Nazism has provided a full century's work for all those who deal with the aberrations of the human mind.

Walter Lacqueur, a distinguished and competent professor of and writer on international affairs, has chosen one particular and perplexing aspect of Nazism: How much did the German people, the outside world, and the potential victims themselves know of Hitler's campaign to systematically wipe out the Jewish population of Europe?

This question has been asked, studied, and debated many times before. The answers depend upon many factors. Those who would excuse widespread ignorance claim that (a) the Gestapo-closed society of Germany kept information on genocide from widely circulating, or (b) since Hitler's "Final Solution" so far surpassed all other modern horrors, it was impossible for most human beings to believe that such activities were going on. On the other hand, there are those who believe that at least partial knowledge of the extent of Hitler's programs was widespread but that this was pushed aside because (a) to have acknowledged it fully would have interfered with the Allied War effort, (b) to have sought to do anything about it would, given Hitler's mentality, only have increased the tempo of genocide (the so-called Vatican attitude), or (c) endemic anti-Semitism in both Europe and America played its part in reducing condemnation.

The author of this book seems to fall between these two schools, accepting all of the reasons stated above. He believes, and provides ample documentation, that by the end of 1942, when the "scientific" process of genocide in the vast murder factories was just getting under way, world leaders had categorical knowledge of what was going on. Indeed, in December of that year, the leaders of the Allied powers issued a joint condemnation of the program. He also indicates that large numbers of Germans, particularly those in official and military circles, knew what their government was doing.

At the same time he is prepared to accept that many who knew intellectually what was going on found it almost psychologically impossible to grasp the full horror of the Hitler mass-murder program.

he result of all this was that nothing practical was ever done to try either to halt or to mitigate this program, other than for small, sporadic or individual efforts.

Is this surprising? If it is, then ask yourself: What, within the past decade, has the world done to prevent kindred acts in Cambodia, in Uganda, and in Afghanistan? Today, as much as during the period from 1942 to 1945, the world tends to shut its eyes when confronted with moral and physical enormities which violently shock the routine of our ways.

If Lacqueur's book opens no new trails, it does broaden and confirm our knowledge of one aspect of a most terrible period of man's history. And whe would deny that we all need to be continually reminded of the necessity to be more aware of the sufferings of our fellows and to be stronger in our determination to combat the forces that produce suc h anguish?