Instruct: Classify Amazon reviews into positive or negative sentiment
Query: I have two copies of this book.

It may sound funny but I keep one copy in the "library" for schematic reference while pondering new designs and mods, and the other at my workbench. It has the best, most complete collection of vintage Fender schematics and diagrams and plenty of others as well. Also filled with great reference info, tips and tricks. A must have.