The Puzzle of Peri Reis — Kent Conwell

After months of stumbling through catacombs beneath a New Orleans cemetery, evading alligators at Bayou Teche, dodging a band of fanatics searching for an ancient crystal skull, and tracking down the torch man of two clubs on Austin's Sixth Street, Tony Boudreaux wants a rest. So when a San Antonio client offers a ten-thousand-dollar retainer to find a priceless map hidden in his deceased father's den, Tony takes the job.

To his dismay, the simple task of finding a hidden map explodes into a series of attempts on his life and two murders with over half a dozen suspects, all of whom stand to gain from the map, which is rumored to have been ancient even in the time of Alexander the Great.