I've never written reviews on Amazon, but I felt I had to for this book. It's very elegantly written, as he takes the same format as the way one learns software craftsmanship in real life: solving real world problems under the guidance of a mentor.In this scenario, you take the role of a new employee at a company guided by the Ruby expert named Bill, on a one week crash course journey though the object model, method creation, blocks, class internals, and finally putting this all together to write a piece of code that seem oddly familiar to the base files you see in some of the famous gems.The book then goes on and ties this ruby knowledge to a Rails specific lens, examining the internals of ActiveRecord, taking a quick tour of Merb, and then having a glossary of metprogramming "spells" useful for everyday work.