International Commodity Trading
by Ephraim Clark, Jean-Baptiste Lesourd is a fantastic book for the beginner when it comes to commodities. I was surprised how much detail the authors went through. It's probably perfect for someone who does not work specifically in commodities but would like to learn more about what is available in the way of infrastructure, procedures, information, and data. 
In his book 
Frank J. Fabozzi PhD deals extensively with the fundamentals of the commodity markets and the inference and workings of investing in commodities with a long-term view. The book does not uncover the latest technical trading methods, but it will teach you almost everything you need to know about Investments in commodities.