The other thing I like about this book is chapter XV, the bibliography. First we get a long list of non-fiction books on fictional topics. I love books like that. Below is the list. I'm leaving off publisher and date of publication because I'm a lazy ass.
Alien Landscapes, by Robert Holdstock and Malcom Edwards
Authentic Thaumaturgy, by PEI Bonewitz
Beauty and the Beast, by Chriss Achilleos
An Atlas of Fantasy, by J.B. Post
The Complete Guide to Middle Earth, by Robert Foster
The Complete Illustrated Book of the Psychic Sciences, by Walter B. and Litzka Gibson
An Encyclopedia of Fairies, Hobgoblins, Brownies, Bogies, and Other Supernatural Creatures, by Katharine Briggs
The Encyclopedia of Magik & Superstition
The Encyclopedia of Withcraft and Demonology, by Russell Hope Robbins
Faeries, by Brian Froud and Alan Lee
The Fantasy Almanac, by Jeff Rovin
Giants, illustrated by Julek Heller, Carolyn Scrace, and Juan Wijngaard
A Glossary of the Construction, Decoration, and Use of Arms and Armor in All Countrys and in All Times (And Some Closely Related Subjects), by George Cameron Stone
Japanese Short Stories, by Ryunosuke Akutagawa, translated by Takashi Kojima
Magic, White and Black, by Franz Hartmann, M.D.
Martial Arts, by Michel Random
Medieval Warfare, by Terence Wise
Men Of The Earth, by Brian M. Fagan
The Morning of the Magicians, by Louis Pauwels and Jacques Bergier, translated by Rollo Meyers
Mysterious Monsters, by Daniel Farson and Angus Hall
The New Larousse Encyclopedia of Mythology
The Phoenicians, by Donald Harden
Secrets of the Samurai, by Oscar Ratti and Adele Westbrook
Seven Magik Orders, by Shan Mui and Ruth Tabtah
Solar Wind, illustrated by Peter Jones
The Supernatural, by Douglas Hill and Pat Williams
A Tolkien Bestiary, by David Day
Tomorrow and Beyond, edited by Ian Summers
War Through The Ages, by Lynn Montross
Wonder Works, by Michael Whelan
Zoo of the Gods, by Anthony S. Mercatante
Looks mostly like an interesting blend of standard Middle Ages stuff and nerdy occult tomes with a dash of Orientalism for flavor. I always find it fascinating what non-game stuff game authors think their audience should read. Mr. Hargrave also recommends the magazines Alarums and Excursions ("the greatest of all fanzines"), Different Worlds, and Sorcerer's Apprentice.
After the lengthy list of non-fiction resources I expected a long list of fantasy fiction, but Hargave keeps this section very short. He namechecks Robert Asprin and Stephen R. Donaldson. The first Thomas Covenant book is described as "a tour de force on Role-Playing if ever there was one". The entire works of Tolkien are listed as "a must read for every adventure gamer". The Elfquest graphic novels get a mention. And Hargrave notes that Marvel comics are "an unlikely, but valuable source of inspiration". And then there's a memorium to Clark Ashton Smith. The Zothique tales are noted as "the true progenitor of ARDUIN".
I'm not in a rush to run out and buy every book on Hargrave's list, but I do see some intriguing stuff there. I've been meaning to get a copy of the Zothique material for some time, and rereading chapter XV has only renewed that interest. Some of the nonfiction works also look intriguing. And Zoo of the Gods is a great title.