Role-playing games now have their own [pattern language](http://en.wikipedia.org/wiki/Pattern_language) (Wikipedia’s defintion is great) book. Fascinating stuff!
In computer science there is a book called [Design Patterns](http://www.amazon.com/exec/obidos/tg/detail/-/0201633612/104-0265062-8435910?v=glance), which is a spin-off of the architecture book A Pattern Language. Both are classics.
Now a person called **Whitson John Kirk III** has written 250+ pages in a CC-licensed PDF on the parts that make up roleplaying games.
He covers ground from Rolemaster to My Life With Master, so no lack of breadth there.
There are diagrams that condense ideas The pattern *Class Hierarchy* has a picture on how character careers lock into each other in games that support characters that advance in their chosen trade.
I am just amazed by this, so please read this, or parts of it. Christopher Alexander’s book on architecture has a lot of talk about how important it is to not read the whole thing in one go, eat it piecemeal. Otherwise you’ll get bogged down in details. So, one pattern a day. No more.
**Download** it here: Design Patterns of Successful Roleplaying Games (.zip) by Whitson John Kirk III. (CC license!)
Via: [Jason Morningstar](http://www.meekmok.com/sassy/archives/002916.html).