Wall Of Serpents by L. Sprague de Camp and Fletcher Pratt $3 Dell Books (1969) 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 friend Reed Chalmers 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 didn't always work 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 he travelled to held countless dangers that even Shea's equations couldn't predict... Cover art by Maelo Cintron. . Overall Poor Condition, Front Cover Ripped In Two Places (Rips are 3" and 1.5"), Readable Copy . . . #wallofserpents #lspraguedecamp #fletcherpratt #paperbacksciencefiction https://www.instagram.com/p/B1T1zUUAALr/?igshid=avvz4ga30d5l