Now that there's an index in the back, its a whole lot easier to use.
Start by looking up things like "Metallic Outlet Boxes", QCIT, or "Nonmetallic Outlet Boxes", QCMZ, and give them a read. That is, look up the most common material that you use, for starters. You'll be surprised at the things you'll discover about the material you thought you knew.
It takes a bit of doing to learn what UL calls a certain thing, but its, worth it in my opinion.
Charlie Bob, you can "profit from it" by using the materials in the ways that UL limits them to being used. A lot of that information is not in the NEC. It'll save you tear out and replace effort and cost.