Wall of Serpents

"The mathematics of magic - it was the greatest discovery ever, or so thought Professor Harold Shea. With the proper equations he could instantly transport himself and his long-suffering colleagues back - or sideways - in time to all the wondrous lands of ancient myth and legend....But slips in time were a hazard. And Shea's magic sometimes backfired...."

The Mathematics of Magic was probably the greatest discovery of the ages - at least Professor Harold Shea thought so. With the proper equations, he could instantly transport himself back in time to all the 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 . . . The Wall of Serpents is the third in L. Sprague de Camp and Fletcher Pratt's much-loved Compleat Enchanter series.