The Encyclopedia of Evil was an ancient artifact in the animated series The New Adventures of He-Man.
The encyclopeia of evil was set of evil spell books hidden away in the Vaults of Zaktus. The Vault was hidden under Grot's Garden near the Oasis on the planet Primus. Legend has it, that due to the tremendous pressures that built up in the core of Primus, the good Primans decided to blast a huge chunk of their planet containing the evil Nordor Crystal off into space. It ended up orbiting Primus and became known as it's moon Nordor. Within Nordor, Skeletor found the first volume of the Encycopdia of evil and set his mind on obtaining all the remaining volumes as well.
The complete set was ultimately destroyed in the Vaults of Zaktus in the everlasting fire cauldron thanks to the combined efforts of He-Man, Teela and Mara.