I have that book in my library, and I concur with Morick. It covers an aspect of buccaneers and pirates of the 17th centuries that is often mentioned, but glossed over. I'm talking about the "buddy" system the buccaneers had, mateloge, I think is the term.
Since not a lot of historical documentation exists on the topic, it is written from the modern perspective and in a sense speculates on what relationships were like, etc. It is a serious, scholarly work.