Books on various programming languages are a dime a dozen. There are a lot of really good books available and there are a lot of really terrible books available.
But if you’re ever read The C Programming Language by K&R or if you’ve ever read JavaScript: The Good Parts by Douglas Crockford, then you know just how good books that cover an entire programming language can be.
Granted, not all languages are supporting material like this, but Ruby does!

Programming Ruby – also known as the Pickaxe Book – is the authoritative book on the Ruby language and the Pragmatic Programmers are currently running this book for $10!
Update 11/29. At the time of publishing this article, the book was running for $10. It looks as if the price has now returned to $45. I still highly recommend this book even if the deal has expired.
Update 11/30: It looks like the sale is still on and they’ve updated the book’s page to reflect the discounted price.
No strings attached, either. It’s their 10th anniversary and in honor of that, they’ve discounted the price.
If you’re at all interested in learning Ruby, this is the book to get.

Is there a discount code for this? Or maybe a certain day this discount is available?
If you go to their site it displays $34.95 for the paper book and $25 for the ebook.
Unfortunately, it looks like the sale is over
.
I just updated the post. I still recommend the book despite the price.
Darn! I am not a Ruby developer, but I would have definitely picked it up for $10.
I will just have to be “pragmatic” and keep this book in mind if I ever have to dive into Ruby.
Thanks for the reply.
Try again – looks like the sale is still on and the site has been updated to reflect it
.
Sweetness! Just picked up the ebook copy.
Thanks for keep an eye on this… great buy!
It looks like the sale is still on. The discount is applied in the shopping cart when you buy either the eBook or Paperback (or both).
Thanks for the heads up!
Thanks Don! It also looks like they updated the site to reflect the price change.