Last year, I reported that most of the book Let Over Lambda was posted on the Internet. I recommended that anyone interested in Lisp take a look at it. I still make that recommendation but be warned: you will end up buying the book to read the rest of it. Daniel Higginbotham summed it up best by writing “…holy crap is it exciting to read!”
I agree. As soon as I finished with the on-line parts, I ordered the book despite my resolve to not buy anymore dead tree books. Now I notice that the book is available via iBooks for the bargain price of $13.99. If you have an iPad (or an iPhone and don't mind reading with the small screen) you no longer have an excuse not to read this book.
While reading Let Over Lambda I had the same feeling of delight and discovery that I felt when I first read Structure and Interpretation of Computer Programs. This is only the second book that's affected me that way. If you're a Lisper, you need to read this book. Really.