From publisher blurb: Blasphemous Books and Malevolent Mysteries Tomes of Dark Secrets brings a new level of horror to your 5E campaign with sinister spellbooks and creepy compendiums of eldritch lore that delve deeply into secrets man was not meant to know! You’ll find five richly detailed books of magic herein, each with detailed history and lore, unique secrets to offer, and a terrible price to pay for that power. On the Inverse Calculus of Unseen Refraction probes the unseen depths of alchemy, invisibility, and never having to look yourself in the mirror. Sepulchral Swaths of Tanoth-Gha, a cultic treatise to primordial things venerated in the dawn ages before civilization yet arose. Spellbones of the Devourer, an engraved fetish of primitive cannibal cultists. The Necrotic Verses, a musical magnum opus of madness and misery. To Serve a Prince Undying, a paean to purity and perfection, the sin of mercy, the virtue of fear, and the triumph of the will.