Dungeon Master of Middle-earth
The Holmes Basic Set blue booklet was my first D&D book. I'm not sure what happened to the box, but I remember having the blue dice and the original version of B2 which came with the set (and which I still possess). Like others here, I played with these rules interchangeably with the AD&D books that were out at the time. Holmes Basic is particularly compatible with the AD&D Monster Manual which was released in the same year (1977) and shares with it five-point alignment. It's also nearly identical to OD&D (1974) so much so that I consider them the same edition and was tempted to answer in the other poll that I had played it although we were using Holmes. Some of the characters that I made with Holmes were later converted to AD&D using the PHB, at which point I realized the two systems weren't entirely compatible.