To publish a book about present-day. China has its calculated risks, and this one has certain chancy elements: it is based on a tour made in 1965 and was originally published in France. K. S. Karol was born in Poland and lived there until the Nazis invaded, when he was sixteen; he then escaped to Russia. After the war, disillusioned by Stalinism (but not, apparently, by Communism), he settled in France, where he became a correspondent for the British New Statesman. His insights into China thus have several unique advantages over those of most Westerners: the popular equation of Maoism with Stalinism does not tempt him) he knows the latter too well, and is able to detect the basic differences. He foresaw the Red Guards and their ""Cultural Revolution,"" and he interprets them not as a sign of weakness and confusion, but rather as a ""new pressure of egalitarianism and militancy,"" intended to prepare the nation for ""prolonged armed Struggle"" with the United States. Whatever one's own persuasion in these matters, Mr. Karol's book should not be ignored; he is an astute political observer whose past experience allows him in this case to be both sympathetic towards his subject and at the same time remarkably detached.