Fellow blogger Lizard at Lizardgames makes a very good point about the old school movement. Namely that the brevity of the rule books were not a goal but a necessity of economics. The small fledgling RPG companies had little money to publish large volumes. Notice in the first years of D&D there were constant expansions to the rules. Magazine articles, adventure modules with extra rules and the supplements all added to the complexity of the first set of rules. They published as often as they could afford. Then the money did come. What did TSR do when they did have increased resources ? They published a lot more books. And bigger books with more pages and better artwork. And of course more rules. I don't think they did it because of the money. They did it because it was what we wanted. Back in the early days if a company produced a game and stopped with only the barest of rules framework. And then said "fill in the rest of the stuff by yourself thats it theres no more". They would have gone out of business quickly. My early days of roleplaying were usually dominated by a quest for more realism. I wanted more detailed rules to make gameplay more lifelike. I look back on those days fondly but I laugh at my attempts at real life simulation. I just wanted things in the game to make sense to me. But I wasn't dong anything different from what my friends where doing. No one forced the books on us. We happily bought as many as we could afford. They added new ideas to our games. The devil may be in the details but we willingly danced to his tune.
There have been questions about what old school is. Thanks to that essay I can now give my version.
Old school is a new term for an attitude about the style of a play inspired the earliest editions of D&D and other RPGs.