THERE has always been a certain fascination in idle speculation of the past. Men wonder how their own lives would have been effected if they had gone into business rather than medicine, or they ponder on what France would be today if Napoleon had won at Waterloo. There is a sentimental romance about the process that appeals to the most prosaic of men.

This weakness, if it is a weakness, has been capitalized by the Viking Press. It permitted several eminent men of letters to wonder about the state of society if Booth had missed Lincoln, or if the Moors had won in Spain. The result is a very entertaining little volume of essays which will offer a pleasant evening and perhaps, occasional moments of regret. It must have been a truly delightful task that these men undertook, for no scholar can find them in error.

It is, of course, impossible to give any detailed criticism of all the essays the little volume contains. Perhaps the most delightful of all is Philip Guedalla's conception of the world if the Moors had won in Spain. He gives Baedeker descriptions, Reuter dispatches, and chapters from spurious histories on the rise of the Moorish civilization. Hilaire Belloc is pretty sure that steamships and locomotives would be still figments of diseased imaginations if Louis XVI had escaped at Varenne's. Emil Ludwig gives a very interesting description of Germany if the Emperor Frederick had not died of cancer in 1888. Unfortunately he is unable to resist the temptation for cheap dramatic effect to which he so frequently falls a prey even in what one might call his more scholarly commentaries. He allows Kaiser William II to assume the throne August 1, 1914 amidst "peace and prosperity."

It is fortunate that all, and there are eleven, authors attack their task in the proper spirit. Every man writes with his tongue in his cheek which allows sly digs and graceful whimsy. "If" is meant purely for purposes of entertainment and it will fulfill that purpose for those people who have an atom of imagination about them.