Paper is tree-based. Developer documentation, if available, is a great thing. It is even better if you can actually find the piece of information you are looking for. Most documentation I have seen is organized in one big hierarchical tree. It’s impossible to find anything until you have intimate knowledge of the tree itself. The problem is often that the information itself is not structured enough to naturally fit in a single hierarchical tree, but it is pressed into it because it appears to be the only way to structure things.