That's not too bad considering the content is equivalent to a first year graduate course textbook.

Which would likely cost $200 or so new, in current textbook market. So $22 is a bit better than "not too bad".

It's awesome that it's freely available.

Heads up - you can use the promo code `print-is-good-F15` to get 10% off. I chose to get a nicer binding and with the code it came to about $23.20