I've just come across an excellent tech reference for OS X. Last week I posted in Applications about an arcane app problem that I had with Photoshop. Nobody among my circle of knowledgable friends understood it, including a couple of ADC members. More than 100 MacNN readers looked at my post, but nobody even offered a guess at a solution.
In a Web search today I came across these pages:
http://www.thexlab.com/book/troubleshootingmacosx.html
The author of this FAQ sells an OS X tech reference book, so I mailed him asking if he thought his book contained the answer to my problem. He wrote back immediately, kindly quoting the page that explained and solved my tricky situation, which was due to a corrupted Launch Services cache. I just bought his book. Over 600 pages of solid tech advice for a $20 download. Looks like a great bargain to me.