Instruct: Classify Amazon reviews into positive or negative sentiment
Query: If you use Emacs, this book will be your best friend.

One of the best computer books ever. If you use Unix, you must have this book. Emacs is one of the fastest and best text editors available, but it is difficult to learn how to use it. This book is clearly written and has an excellent index which points you right to what you are looking for. The reference card is also very convenient. Buy this book!