This book is a collection of five short stories, written by the incomparable H. Beam Piper, and set in his Paratime universe (or more correctly, multiverse). In this milieu, human society has developed the technology to move laterally between parallel universes. This advanced society looks upon itself as 'First Level'. Second Level contains societies that are about as advanced as First Level, Third Level is less advanced, our own 'Europo-American' world is firmly on the Fourth Level, and Fifth Level contains worlds where (for one reason or another) human life does not exist. Within each of these levels (except First), there are many parallel worlds, many only marginally different, and totaling up to ten-to-the-hundred-thousandth time-lines! Protecting the secret of the existence of this multiverse is the Paratime Police, and these are their stories. 1) He Walked Around The Horses reveals the fate of an unfortunate Napoleonic diplomat accidentally moved to a parallel time-line where the American and French Revolutions were crushed. 2) Police Operation introduces Verkan Vall, Special Chief's Assistant, who needs to clean up a dangerous Venusian pet, which was accidentally left on our time-line. 3) In Last Enemy, a Second Level society has scientifically proven reincarnation, and now it's up to Vall to rescue his ex-wife Hadron Dalla from the resulting explosion. 4) Time Crime pits Vall and the Paratime Police against a well-organized band of criminals, who are jeopardizing the Paratime secret. 5) And, in Temple Trouble, when a group of First Level workers fall into the hands of a Fourth Level king, it's up to Vall to ensure that the Paratime secret isn't wrung from them.