An excellent video just came to my attention and adventuring along in the spirit of the D&D 40th anniversary, I present it to you below with no delay. This guy did a good job of covering a lot of information very quickly. I love this kind of nerd history / nostalgia.
By the way, the video’s creator is Jon Peterson, author of the Playing at the World book and blogger of RPG history. You can follow him on Twitter at @docetist. I like his style.
A History of D&D in 12 Treasures