It was ok. Despite the title, the book does little to explain the mechanics of supernoae and GBRs. It spends about half a chapter going over how each type of SN works and about a page going over how GBRs work. The rest of the time it spends talking about how astronomers use the two to work out distances and how the universe is evolving. Fantastic, but not what I got the book for. If I wanted to know about the evolving universe and what objects are being used for standard candles I would have bought "Exploding Superstars: How we use big explosions to map distances". As for the information it did present, I found it very informative. They authors go into great detail about the methods of distance marking and redshift analysis as well as the future of these methods. But like I said, I got the book for explanation about the bangs, not the uses we have for them. ( )