I'll throw my 2pesos in as well and concur here. Though I do feel the pain of traversing down the call stack to dig up where the magic is. Ruby for Rails has a

I'll throw my 2pesos in as well and concur here. Though I do feel the pain of traversing down the call stack to dig up where the magic is. Ruby for Rails has a great chapter on digging into Rails core code which helped me a lot.