Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Educational, enlightening, and amazing!

John Vacca never ceases to amaze me with the wealth of information he is able to put into a very concise yet understandable format. His latest book, Satellite Encryption, is no exception. John's books take you by the hand and guides you down a path of very complex subjects and issues, making sure you don't get lost. In the end you will feel the journey was well worth the effort.