Published by TSR originally, reprinted by many different companies over the years.
Empire of the Petal Throne is my favorite game I’ve never played. Oh, I’ve played in Tékumel before, but I never used the original 1975 TSR-published rules. I think that’s a great shame, because, as OD&D rules variants go — and that’s more or less what EPT is — it’s hard to beat this game. For old schoolers looking for some intriguing alternatives to the way OD&D handles things, it’s well worth reading.
Read the Full Retrospective/Review at Grognardia.