Every lost treasure you could imagine
The amazing, colossal, stupendous complete (as far as we know) compendium of lost treasures from 1911. Not just pirate treasure or Spanish armada treasure, but also the lost treasures of El Dorado at the bottom of Lake Guatavita -- and the unsuccessful efforts thus far to recover them. It also has three chapters on Captain Kidd, who was not really a pirate but a privateer, with a thin wavering line between the two ( I recommend the excellent "Pirate Hunter" for the definitive Kidd book.) Several hard-to-find period photographs and sketches enliven the volume, and are recommended. An ultimate reference. I should warn you tho, that several places cited are now off limits to digging, having been declared natural or historical preserves.