After having played havoc with the best seller lists when he wrote "Inside Europe" and "Inside Asia," John Gunther might well be expected to crash through with another attempt to get "inside" some place or other. And that is exactly what he's done in "Inside Latin America," a racy and thoroughly informative sketch of Latin America, plays Puerto Rico and Trinidad.

Necessarily more of a summary than either of his other books, "Inside Latin America" is fascinating, up-to-the-minute news of the other nations of our hemisphere: of their problems and personalities, their histories, economics, and politics, their Fifth Columns, their fear and desires, their rivalries and alliances.

Gunther does not attempt to give us a scholarly account of the social or economic background of any of the countries he talks about. Such a task would be far beyond his capabilities or ambitions, he asserts. Instead, he has chosen to present a smooth-running account of what he saw and heard in his tour of Lain America. One cannot but marvel that he should so neatly and unfailingly pick out the right amount and mixture of facts, figures, and opinions on which to make his representative characters speak and move about. He is particularly good on such important personalities as Vargas, Comacho, Batista, and de la Tarremen who may turn out to be more important to us than Hess or Beaverbrook or Petain.

There is a lesson for this country, too, contained in Mr. Gunther's volume. It is that we are making a big mistake if we think there is such a thing as an entity of Latin America. Argentina, with its fierce nationalistic complex, differs utterly from gay, easy-going Brazil. Chile has a progressive Popular Front government, Nicaragua is an absolute dictatorship. In short, to understand our neighbors we must understand not one, but twenty one peoples.

Mr. Gunther has a lot to say--and he says it often and well-about the role the Nazis are playing in South America. But his fears are outweighed by his optimism about the intra-continental solidarity he feels is being rapidly established. His book is a valuable piece of work, enormously readable, and full of those neat Guntherian tricks that make him one of our top-notch reporters.