What sorts of books should I avoid buying if I can get more or less identical information on the Internet such as Wikipedia? For example are any of the For Dummies or Complete Idiot’s Guides information have stuff that can’t be found by Google (either in way of facts or by way of interpretation?)
I think you can find just about everything free on the net.
However, a book compiles it all in an easily-readable manner, in one place. If you’d rather spend hours & hours digging through websites of various qualities to find the same info, I’m guessing you could. But I find that if a book gets good reviews, it’s generally worth the money, because it’s just all right there in one easy spot.
Put it this way: I’m a programmer. I have to keep up on new technologies. Because us programmers wrote the Internet, there’s not a damn thing I can’t learn if I find the right website. Still, if I really need to learn something, I generally will find a well-regarded book and buy it. Having everything I need, written by a reputable source, in one spot is worth it to me.