This is a short little book that's a fun read to help you better understand the science behind much of brewing. $15 is over priced and I'm not sure I'd pay that. I got it as a gift and it's definitely worth free or a bit more if it's ever on sale. Otherwise you can get other books with a lot more useful information for that price.

Goes lightly into many technical subjects.

If you don't have a Chemistry background this book does a nice job conveying some of the concepts used in brewing. It even has pictures of molecules so you can visualize what an enzyme does. It might not help your brewing much but it will help your understanding of whats happening and why.