Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Excellent

This book is unique within the field of training Guard Dogs. As the book was written in the 1960's it provides the reader with insight into the history of how dog guards were selected and trained. Many of the techniques and topics apply as readily today as they did when the book was written. The author's experience speaks for itself, adding weight and credibility to overall content of the book.