Michael D. Mearls (born February 13, 1975) is one of the most productive and popular game designers. Currently he is the lead developer of D&D4. He has worked for several companies contributing to the following books:
- Wizards of the Coast
- Fiendish Codex II: Tyrants of the Nine Hells
- Player's Handbook II
- Power of Faerûn
- Malhavoc Press
- Book of Iron Might
- Book of Hallowed Might II: Portents and Visions
- Book of Roguish Luck
- The Giant's Map
- Iron Heroes
- Iron Heroes Bestiary
- The King Must Die!
- Legacy of the Dragons
- Looking Glass Deep
- Mastering Iron Heroes
- The Thrice-Cursed Crown
- Goodman Games
- Aerial Adventure Guide series
- Underdark Adventure Guide
- Paradigm Concepts
- Slaves to the Moon
- Atlas Games
- In the Belly of the Beast
- Touched by the Gods
- Fiery Dragon Productions
- Nature's Fury
- To Stand on Hallowed Ground
- Psionics Toolkit
- Mongoose Publishing
- Quintessential Rogue
- Quintessential Wizard
- Alderac Entertainment Group
- Folnar’s Dagger
- The Prison City of Hell’s Reach
- Evil (AEG)
- Dungeons (AEG)
- Dragons (AEG)
- Undead (AEG)
- War (AEG)
- Monsters (AEG)
- Mercenaries (AEG)
- Magic (AEG)
- Good (AEG)
- Gods (AEG)
- Wilds (AEG)
- Empire (AEG)
- Relics (AEG)
- Swashbuckling Adventures
- Fantasy Flight Games
- Daggers at Midnight
- Darwell’s Tower
- Mythic Races
- Seafarer’s Handbook
- Monster's Handbook
- Dungeoncraft
- Cityworks
- Wildlands
- Portals and Planes
- Necromancer Games
- The Siege of Durgam’s Folly
- Lost Garden
- Sword and Sorcery Studios
- Relics and Rituals
- Creature Collection II
- Blood Bayou
- Scarred Lands Campaign Setting: Ghelspad
He is also the author of Plain English Role Playing game.