delericho
Legend
Some of those are a little bit higher than the info I was using but a few match up with what others have said. I had seen the 2E figures before an never added up the 1E books. 1E would be the biggest D&D version ever based on those numbers (I thought it was the Red Boxed set).
https://www.acaeum.com/library/printrun.html
Yeah, I've heard previously that the B/X Basic Set was the best-selling version ever. Though it's possible that it's actually the case that it was the "Red Box", but that that's actually split between the B/X and BECMI versions - thus "splitting the vote" sufficiently that neither quite takes the title alone.
Alternately, it's likely that all these approximations have been at least a little skewed by time.