When Gary Gygax died in March, several eulogists observed that this co-creator of Dungeons & Dragons had made a big imprint on our computer culture. It's hard to believe that the online game World of Warcraft, for example, would boast more than 10 million subscribers today had Gygax and Dave Arneson not come along first, calculating the armor class of bugbears and determining the number of experience points paladins need to move up a level.

The underlying assumption was that Dungeons & Dragons had slipped into nerdy nostalgia....