I started this project after a friend of mine went on a long diatribe about how he had been playing Basic, and by Basic he meant Holmes Basic, since it was published and how it was the longest running form of the game.
He was, of course, full of shit as I'm about to demonstrate.
In the chart above you'll find a listing of all the different Dungeons and Dragons systems in order of publication, starting with Chainmail's publication in 1971 and ending with Fourth Edition in 2014.
There are two things you should know though, I end each edition when a new version of the product has come out with substantial changes to the product. So Holmes Basic ends when Moldvay Basic comes out; which, in turn, ends when Mentzer Basic comes out. Secondly, I'm only showing dates by the years and refuse to adjust them to the months. If you want to be that neurotic then you can go out and make your own chart.
Anyway, I hope that this will be of some use to other folks when they're having this argument.