I find it irresistible to keep purchasing cheap programming and technical e-books in fields such as Drupal, PHP, etc., and also compulsively download free material made available such as those from Microsoft's developer blog...

The main problem with the large library I've developed is that there are many chapters (especially the first few) in these books packed with information I already know, but with helpful tidbits hidden in between. The logical step would be to skip those chapters and read the ones I don't seem to know anything about, but I'm afraid I may lose out on really important information this way. But naturally it is tedious to have to read about variables, functions and objects all over again when you are trying to know more about the Registry pattern, for example.

It's hard to research on the net for this, because my question itself seems vague and difficult to formulate into a single search query. I need people-advice - what do you do in this situation?