THERE may be more vehement critics of Nazi Germany, but none yet are so eloquent as Thomas Mann. In his latest book, "This Peace," he propounds the theory that "in the guise of hypocrisy and demoralized pacifism" Czechoslovakia was betrayed by European democracies so that Fascism would be strengthened for its role as hired gunman against Russia--a role which Hitler promises to play in "Mein Kampf." This brief essay condemns, in language at once controlled and vitriolic, the "pro-fascist" English statesmen for their leading role in this "foulest page of modern history."

In what is an entertaining but not very profound analysis, Mann describes Spanish non-intervention as a "transparent, disingenuous comedy," and terms it merely the first step in the cumulative, knavery which led to Berchtesgaden; the war scare, he says, was merely a cruel theatrical joke played on the masses of people, straining their nerves to the cracking point until they would overlook Czechoslovakia's betrayal in their gratitude for the avoidance of war.

In despair, Mann cries "Madness, thou hast prevailed!" yet almost in the next breath he offers "eternal" hope. Fascism, he says, will rapidly dominate the continent,which will then become a United States of Europe. Then the trashy ideology which served as a vehicle on the road to Fascist domination will have become superfluous, for, just as Fascism excludes peace, peace excludes Fascism.

Unfortunately, as David Popper has pointed out, Mann has based his essay entirely on a theory whose truth is yet to be proved. The events he ascribes to Machiavellian tactics may be in truth the product of weakness and indecision. "Human drift and stupidity may attain heights beyond imagination, which observers are constantly tempted to ascribe to some planned motives." Nevertheless, the book is worth while for those who are interested in a variety of different interpretations of the historical role of the Munich settlement.