Marina Warner at the New York Review of Books:
If animals are not only bons à manger but also bons à penser (good to eat, good to think with), according to the celebrated dictum of Claude Lévi-Strauss, then monsters, while perhaps less inviting to the palate, make even better food for thought. Themselves the direct and fanciful products of attempts to understand phenomena, they appear in a wonderful variety of forms on the maps drawn up by medieval and Renaissance cartographers, as Joseph Nigg and Chet van Duzer show in two resplendently illustrated and thoughtful recent studies. Scylla and Charybdis, sea serpents and pristers offer a range of explanations for natural phenomena, such as whirlpools and reefs; indeed the abundant stories that Homer and Ovid tell draw up a wonderful narrative geography as much as a mythical history.
Yet in many ways maps and monsters would appear antithetical: maps are about measurement and evidence; they attempt to document a real world out there in an objective way with empirical tools tested over time; by contrast, monsters are fantasies, mostly sparked by terrors, but sometimes born of desiring curiosity, too.