Spreader's Handbook - Bob McGovern
This is a compilation of Bob's many years of continuous spread trading. His favorite spreads are listed on a monthly calendar basis, along with never-before mentioned insights on floor activity and manipulation!

Be a Winner Trading Commodities - Ralph J. Fessenden, Ph.D.
This book is about "scale trading", a sound method of money management that has tremendous psychological advantages. This changed the way I thought about trading. Take seriously the warnings about carrying charges, though!

Commodity Spreads - Courtney Smith
This book covers the basics of commodity spreads.

Option Volatility & Pricing - Sheldon Natenberg
This is a fairly advanced book on the theory and practice of option trading though it begins with the basics.

Winner Take All - William R. Gallacher
Read this book to keep from becoming a victim of the snake-oil salesmen. Lots of schemes are exposed for what they really are.