The Encyclopedia of Fantasy by John Clute and John Grant

A 1999 encyclopedia with an extensive overview of fantasy. Not only movies, authors, and magazines, but also themes. From FOREST and EDIFICE to THINNING.

The thematic entries have a lot of interesting stuff. Though, since they do have a concept of fantasy, works that do not match their template may be discussed with the sound of an ax grinding. (Also some ax grinding on personal topics.)