The major benefit of this book is a comprehensive treatment (i.e., updated diagnoses accompanied by original photographs to illustrate the main diagnostic features plus a glossary of used terms) of all so far known species of the genus Hydroides accompanied by original illustrations, which has not been done before. The authors are excellent researchers with many publications to their credit. It will be very useful to commercial and academic institutions. Students will enjoy collecting and identifying specimens from reefs, harbours and aquaculture facilities. Because Hydroides has world-wide distribution, the book has a worldwide audience. Hydroides biofouling has high economic impact due to the costs associated with removal of the tubes from ship hulls and submerged structures, aquaculture facilities, as well as lost revenue from fouled commercial molluscs. This book thus has economic importance, and will be a useful resource as more research into Hydroides is funded. This book is the first fully-illustrated comprehensive guide to all known to date species of the notorious biofouling and bioinvasive genus of calcareous tubeworms. Quality original micrographs.