I had high hopes for this. I was interested in the mechanics of how the Spanish got their silver (and gold) from the new world back to Spain and the effects this would have, and the blurb for this book made this book sound like just what I was looking for. As it turned out, the book is more a potted history of Western European/Spanish conflicts and exploration described in terms of how these concepts pertained to the fleets. That is, the book was back-to-front from my point of view. Basically, it's about European history, with a bit of indication of how the transportation of silver fit into Spain's imperial pretensions and conflicts with other European powers. The book doesn't really tell you much about the fleets themselves or how exactly they ran.
Even in its own terms, the book isn't very successful. The bibliography is only English, and a lot of the stuff was out of date even when it was published back in 1993. Lots of generalizing works from the 1930s, and the work cited for the Spanish conquest of Mexico is Prescott's work from the 1840s! Basically, the book didn't tell me much I didn't already know. It's full of broad-stroke generalizations about "Spanish decadence" and the like, giving it the sound of an undergraduate honors essay rather than the mature work of full-fledged academic.
The book also seems to have been produced in the first-generation of computer-generated book designs, and its amateurish appearance betrays this. Many of the illustrations are practically "illegible" (very dark and shadowy), and the childish pseudo-Anglo Saxon fonts for the headings are ridiculous. And for some reason, the heaviness of the type changes from paragraph to paragraph. Some are printed with quite thick letters, but all of a sudden one turns up with a much lighter appearance. I have no idea how that happened.