The protocol recommended in this book DOES work, and I think the science behind it is valid. So if you travel across multiple time zones regularly (especially 4 or more), I highly recommend this book. Unfortunately, it's not a very well written book, which is why my rating is lower. It suffers from excruciating repetition and overly scientific lingo. Why say "methylated xanthines" over and over and over when you can just say "caffeine"? I realize that caffeine is only one of several methylated xanthines, but in this book they are used synonymously and it was unnecessary to keep using phrases no one understands instead of phrases everyone understands. Also, there are very obvious questions that are never answered, such as whether you can take caffeine tablets as a substitute for drinking "two to three cups of black coffee." And the protocol is complicated and impractical, so you really have to work at it to pull it off. But in the end you'll get some tools that might help you get over jet lag faster, if you can work through the repetition and get to the meat of what they are proposing, and then diligently follow it.