An omnibus collection of three stories.
The Mathematics of Magic – That was the greatest discovery of the ages... at least Professor Harold Shea thought so. With the proper equations he could instantly transport himself and his buddy Reed Chalmers back in time to all wondrous lands of ancient legend.
But slips in time were a hazard, and Shea's magic did not always work... at least not quite as he expected. A dragon spell might yield a hundred dragons... or, even worse, one tenth of a dragon. And the various imaginary lands to which he traveled – from the land of Thor and Odin to the Castle of Otranto – held countless dangers that Shea could not predict.