OpenBSD is, as usual, selling CDs of their 4.3 release. It appears that related-but-not-directly-linked goods like The Book of PF are being sold right along side.
The sight of a thick technical book with an included (and probably out of date) CD has been common for years; however, this reversal strikes me as a good idea. Selling a good book along with the operating system that will use it is worthwhile.
The book isn’t thick, but it is GOOD. Worth buying if you are serious about pf.