I wouldn't say I "read" bicycle books so much as I consult bicycle books. That's to say that I don't typically pick up a cycling related book and read it cover-to-cover but rather I'll use it as a reference for when I need to look up some handy piece of information much as I consult an encyclopedia. I pick up a few new books every now and then but most of the time, I like to peruse the library system's regular booksales. They usually have something going like, "$5 per grocery bag of books" so I stock up.
Most of the new books I buy are things like trail and ride guides such as the ones from Terragraphics which have excellent maps and route descriptions. One book I really treasure is my personally signed copy of Ned Overend's
Mountain Bike Like a Champion because Ned is my cycling hero and was my inspiration during the early 1990s when I was racing XC. And
Bicycling Science is a great book... especially if you're a technogeek like myself.
Here's a picture of a portion of the somewhat disorganised cycling section of my book shelf. A few books are missing because they're sitting on coffee tables or my desk.