The 3rd Edition of The DCS Companion is an extensive 242-page guide for operating the MTH DCS Digital Command System. The book includes 79 charts and illustrations, all intended to educate the reader on the basic and advanced features and functions of DCS. The 3rd edition explores the newest aspects of DCS, including the latest version of the DCS software, and implementation and operation of DCS using the standard DCS App for smartphones and tablets. The 3rd edition also adds an index that allows quick and easy access to reference information. Reviewed by Jim Barrett in OGR’s January 2010 issue, the original edition was hailed as an “indispensable tool†that “should be in the hands of every command control operatorâ€. The book is a valuable reference for both the experienced DCS operator, as well as those seeking to add DCS for the first time to a new or existing layout. The uncomplicated language used in this book allows anyone to easily understand and operate this command system, regardless of their experience level. Even the most expert DCS operators will find useful information throughout this book. The 3rd edition increases the already extensive breadth and depth of the book. Since each section of the book inherently builds on the previous section, the reader has the choice of starting from the beginning and working their way through the entire book, or jumping to a particular section of interest.