I start, like tjr, with the ToC. Then I check the index (if it's in my hands). Then skim a few chapters - see if the content under interesting chapter headings

I start, like tjr, with the ToC. Then I check the index (if it's in my hands). Then skim a few chapters - see if the content under interesting chapter headings is written well and\or usable by me. Lastly, what is the price? Regardless of cost, if it's not one I'll read over and over \ refer-to constantly, I'll go to the library and check it out for a couple weeks, picking-up what I want/need from it