Ed, it depends. That book may have been the result of a Ph.D. dissertation, and if lucky, the newly-minted doctor was able to revise it and produce a publishable book. It is put out by the U of California Press, one clue leading to that conclusion. Theses and dissertations are often times the accumulation of several course papers on a given topic, massaged together into a larger topic and a longer document.

It's nice if you can get papers published as you write them (for classes), but it isn't always possible. I published a couple while working on my master's degree and that was apparently fairly unusual. (I didn't publish my thesis, it wasn't long enough to be a book.) Not publishing them makes it easier to use them in your dissertation, then you don't have to worry about so many citations (citing yourself). So, waiting isn't all that unusual.