This book continues the strong tradition of field guides produced by Human and DeLoach. If you've used any of their other guides before, you can rest assured that this continues the clear, informative format they've developed over the years. The first flaw that I've come across, however, isn't a problem with what's covered but what's not covered: Salmon.
This field guide is aimed towards scuba divers, so I assume the authors made an editorial choice to focus on the fish likely to be seen by divers. However, if that's the case, then they should have mentioned in their introduction how they decided what to include and what to exclude. Even if the authors think divers are unlikely to focus much on salmon, I think the authors made an incorrect choice to exclude from this book one of the most characteristic groups of fish in this area.