The most basic of questions...

I picked up Photoshop 5 LE a while back - LE would eventually become Photoshop Elements with later releases of the parent program.

Anyway, I'm discovering that I really don't know how to use it. I mean, I can do cropping, resizing, and basic color correction, but these "layer" things are problematic - as in I really don't know how to use them. It makes following the advice in the tutorials rather tricky.

I'm not asking "How do I do layers" here. I am asking for a recommendation of books that will help me with such things.

Thanks. Hopefully I'm not too far off-topic here.