Actually, ALT-A is totally correct - by very strict standards, D&D is nothing but the original three books that had the "Gygax and Arneson" names on them. The purists can argue that as soon as the next three little books came out, it wasn't D&D any more.
Then, when that horrid AD&D came out, it REALLY wasn't D&D any more.
Which is why I have played D&ME for over 30 years... and that is pronounced "DEE AND ME". Sure, I might use the (insert certain edition here) books, but I've personalized it from the I picked up my DM hat and did a horrid job of turning "The Martian Chronicles" into a setting (as in: Edgar Rice Burroughs' series). It's been all downhill from then.