I love the idea of turning this into a book, yet the problem with a book is that due to how fast rails moves, the actual content would eventually become outdated.
Agreed - most books become outdated by the time they reach the bookshelves.
I'm saying more of a book approach than a screencast approach. Most books start at the ground up, with each chapter building on the previous, while many screencasts tend to be independent of previous episodes.
