I find the book fascinating, never having done more than dabble with nroff, troff and the like. It seems a touch dated, but interesting nonetheless. I'm not sure I'd recommend it for a sed beginner though.

I don't have a book recommendation to offer in return, having taught myself to use sed from manual pages and so forth. I started using sed on a DEC VAXCluster running VMS in the late 1980's. It had been ported to VMS from Unix and made my life much simpler, since VMS wasn't that good at doing this sort of editing.