The Art of Language Invention: From Horse-Lords to Dark Elves to Sand Worms, the Words Behind World-Building

The Outlandish Companion Volume Two: The Companion to The Fiery Cross, A Breath of Snow and Ashes, An Echo in the Bone, and Written in My Own Heart's Blood (Outlander)

Companion to Narnia, Revised Edition: A Complete Guide to the Magical World of C.S. Lewis's The Chronicles of Narnia

The Language of the Night: Essays on Writing, Science Fiction, and Fantasy

Planet Narnia: The Seven Heavens in the Imagination of C. S. Lewis

Afrofuturism: The World of Black Sci-Fi and Fantasy Culture

The Hobbit Encyclopedia

The Ring of Words: Tolkien and the Oxford English Dictionary

Bandersnatch: C.S. Lewis, J.R.R. Tolkien, and the Creative Collaboration of the Inklings

Lord of the Rings and the Eucharist