If you come from a working class background, this book will piss you off. Did you know that people who work as carpenters don't know how to problem solve or analyze client needs? And here's a gem: "... the tendency of [library] staff is to slip into focus on what is easy for them..." Ah, the classic complaints of the gentry about the hired help being shiftless. The authors devote a lot a words to stressing the importance of keeping the wrong people from getting notions about their own worth.
But if you can ignore those passages, there is some useful information. You just have to engage in a fair amount of winnowing to separate the wheat and the chaff.