I would like to introduce our new book entitled: Recirculating Aquaculture. This book (now in its 2nd edition) replaces my previous book entitled: Recirculating Aquaculture Systems which is now out of print. The original textbook was used as the primary resource for the Cornell University Short course which I started in 1994 and an undergraduate course on recirculating aquaculture principles in 1985. The new book has been expanded roughly by 200 pages. We added a new chapter on denitrification (by Dr. Jaap vin Rijn) and expanded the biofiltration-nitrification chapter into two chapters (one on processes and the other on design). Also of special interest is a chapter on aquaponics written by Dr. James Rakocy from the University of the Virgin Islands, which was added to the 2nd edition of the original text. We think the text effectively covers basic fish management and aquaponics as well as addressing all aspects on the design and management of recirculating aquaculture systems. We have also made the book's software available on the CAV website along with additional software that you will find useful, e.g., pH, alkalinity, carbon dioxide spreadsheets for fresh or saltwater. Software on our website that is described in the book s Appendix includes the following: a) fish tank design, b) carbon dioxide control, c) fish farm economic analysis, d) pipe flow friction losses, e) LHO and dissolved gas concentrations, f) air lift pumps. The software programs are a nice compliment to the book chapters that give the basic theory and mathematical calculations behind so many of the design problems that face aquaculturalists. The text book is fully referenced and provides a very complete list of tables on conversion factors and other pertinent information specific for aquaculture. Several chapters are written by authors who are well known in the aquaculture community and combined have over 100 years of experience in aquacultural engineering. All are prominent members of the Aquacultural Engineering Society.