The Book of Imaginary Beings, by Jorge Luis Borges, Peter Sis (Illustrator), Andrew Hurley (translator).
Borges is one of my favorite writers. Hyperintelligent, funny, bizarre, fantastic without being self-indulgent, cryptic without being annoying, calm. civilized, and an obsessive craftsman of words. I want to learn Argentine Spanish just to read him in the original, sometimes.
This work is a compendium of 116 imaginary beings from myths and stories, some well-known and others deeply obscure, some from traditions and others from more recent authors. It’s almost literally magical to me. If you don’t have the cash or the interest to buy it, there’s a nicely done web interpretation of the book. A sample: The Eater of the Dead.