A very good book. Focused mostly on the Americas cup yachts, from the original 1851 race thru the turn of the century, and a little coverage into the 1960's. Certainly not all the boats, but the "highlight" reel, with enough background and details to make each story intersting.
The book finishes with a chapter or two on other races, the around-the-world, caribbean, etc, but all covered rather lightly.
Not knowing much about the Americas cup, its origins or the boats and evolving rule, I found it very good. If you know it well already, this is probably not the book for you.