The Great Sea-Serpent, first published by A. C. Oudemans in 1892, is a foundational text in cryptozoology. Oudemans did more than just compile a lengthy list of sighting reports-he used those accounts to thoughtfully develop one of the most interesting theories in the historical investigation of mystery animals. While we may or may not agree with his conclusions, we can see the direct influence his methodology had on the pioneers of cryptozoological research. Even today, there are few studies that match the scope, detail, and effort of The Great Sea-Serpent. It is worth a space on any cryptozoology enthusiast's bookshelf.