[Crossroads of Time] is a well-written introduction to the concept of parallel worlds. It becomes slightly sidetracked when Blake is forced into his overlong ordeal through worlds not really connected with the plot, and Blake himself spends a lot of time being bewildered (though understandably so). However, the action and tension remain constant, and the settings are fascinatingly exotic. This 1956 novel displays its Cold War era origins in its gloomy succession of time-lines in which Earth has always been destroyed in a nuclear or similarly castastrophic war; but this supports Blake's resolution to keep the same fate from being brought by Pranj to our own world. There is an equally good sequel, Quest Crosstime …, in which Blake goes on his first mission as a full-fledged Wardsman into an alternate America dominated by a militaristic Aztec/Toltec society. (p. 8)