I like books about the restaurant business and I'm interested in the sea and the history of commerce and commodities, and I like sushi, so that's why I grabbed the book off the library's new book shelves. I finished it in two days because it's pretty well written.
It takes you on a meandering tour of the sushi world, focusing on bluefin tuna, from the point of view of restauranteurs, auction houses, fishmongers, tuna ranchers (I certainly didn't know there was any such thing) and more. Each chapter introduces a specific person and describes what that person does in the global market.
I will keep the little Seafood Watch card in my wallet (which says I should avoid bluefin tuna anyway - which is fine because apparently it never comes near my local sushi joints, nor could I afford it if it did). But I will never imagine again that I can know where any fish came from.