I try to do the opposite. I ignore the books I have when selecting the next book to read, and try to determine what's most important. Then, if I already have it, I'll read it, and if not, I'll get it. It takes a relatively long time to read a book, so it's worth it to me to get the one I want to read most, and pay for it if I have to.
I have a huge library of books (and I have read many of them), and still find pressing topics I need to know which are not covered by any of the books I have (and neither seemingly by the Internet at least till I discover some relevant keywords).
An additional thing is that I have read through the introductions of a lot more books, and that by itself gives a first understanding of the subject.