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

I figured, gee it's just a few bucks, what the heck.Well, this is one book which doesn't look to spend much time on the shelf. It's not exhaustive (it tends to be focused on the basic european instruments so includes e.g., violins, brass and guitars, but omits the cuatro, ney, sitar, etc.) but seems to be error-free. It won't necessarily obviate occasional discussions of capabilities of the instrument with a player, but is quite handy nevertheless. This is exactly the book that I wish I had twenty years ago.