[to3m]

Well, maybe not an entire 500 page book, though I'm sure it wouldn't hurt. You could always try Zed Shaw's the-hard-way book on the subject: http://regex.learncodethehardway.org/book/ (haven't read it but the the-hard-way books seem to be fairly well regarded)

I do take issue with your suggestion that you might not use this stuff all that frequently in your career. This is definitely at odds with my experience. Even though I don't use them that much in final-quality code, I use them all the time from the text editor, and quite often for quick one-off text manipulation or extraction scripts. Having a quick way to extract text from ad-hoc data can quickly get you a rough answer to a speculative question, the text equivalent of of back-of-the-envelope calculation, without needing to do a lot of work and without needing the question to justify a lot of work.

But I mainly use them for searching for one of two or three different strings in the text editor.