From the publishers blurb:
Part zine, part mini-splat book,
Wherein Evil Lies includes a host of evil and undead resources for classic/BX editions...
Including:
3 new classes: Deathslayer, Witch Doctor, Half-orc (Assassin)
9 new spells: fatigue, death rage, mummy's touch, ossify, revenance, wailing fear, necrotic portal, greater ossify, aura of fear
6 new magic items: equinox orb, fiendish mantle, hammer of salvation, plague mace, purity ring, stole of radiance
7 new basic psionic abilities: infuse terror, psychic vampire, destiny dissonance, aura of fear, psionic daze, crisis of breath, shadow twin
6 new monsters: atori, cackler, crypt riddler, korper, hill haunt, spawn of Chuamisi
optional rules for killing vampires
new petty god & minion: Anguia Umbra (petty god of iophilia, toxicophilia, assassins) and his chimera minion/familiar Azamus
a new adventure for 5-7 characters of 3rd-5th level: The Black Chapel
3 new d30 tables: quirks caused by becoming unhinged, methods of sacrifice, evil hooks & seeds for encounters and adventures