Published by Wizards of the Coast.
This is probably the most widely owned and played module of all time. It was included in many editions of the Holmes Basic set and all the Moldvay Basic sets, as well as sold separately. There are two slightly different versions of this module, one for the Holmes box and one for the Moldvay box. Although the differences in game play between the two are minimal.
Read the Full Review at Dragonsfoot
Although I contend that The Village of Hommlet, about which I’ve already written a retrospective, is the greatest exemplar of Gary Gygax’s remarkable skills as a designer of adventure modules, I recognize that this is a minority opinion. There’s a peculiarly large contingent of gamers who dislike module T1, a sentiment I find baffling. Far more gamers, if asked to choose their favorite Gygax-penned module, would choose The Keep on the Borderlands. To some extent, I suppose such a choice is inevitable, given that module B2 was packaged with the Moldvay Basic Set, through which perhaps more gamers entered the hobby than any other. For these gamers, The Keep is where they first took up their swords and donned their shields in defense of the Realm against the depredations of Chaos. It’s a touchstone for an entire gaming generation in a way that the better-crafted Hommlet is not.
Read the Full Retrospective/Review at Grognardia.