From the cover:
"A sourcebook of Forbidden Lore for the Mazes & Minotaurs roleplaying game."
From the title page:
"Read this Word of Warning!"
"The character classes and mythic items described in this book are not suitable for all campaigns. At best, they are anti-heroic, at worst outright villains and should thus be only used as NPCs. Most self-respecting heroic characters would never associate with them, and neither will NPCs. It will require some care to let them be PCs, and probably some mature players."