Infernal Realms is the next supplement to Pits & Perils, adding loads of new content while preserving its old-school style and simplicity. This booklet has:

• Variant classes, including hill dwarves, barbarians, and swashbuckling corsairs!
  
• Alternate armor rules and material components to enhance spell casting powers, not to mention exciting new spells. Open black holes or put jinxes on your foes!
  
• New rules. Go berserk or tame monstrous mounts. But beware demonic possession!
  
• Many new enemies to fight (including the Hosts of Hell) and magical items to win and wield. But beware, not all that glitters is gold, and some of these are cursed!
  
• Miscellaneous rules and resources for managing a campaign, all in a 50-page booklet!
  

Infernal Realms rounds out the Pits & Perils experience, for a total of 10 classes, 51 spells, and nearly 200 enemies and 400 magic items when you get all three books! Simple rules can still be robust!