My 2¢ -
Keep in mind - there are many, many books on "Marketing" that really having nothing to do with Marketing and more to do with seperating a person's money from them. Most commodity books deal with "speculating".
Marketing what you grow is entirelly different them speculating and different then buying if you are a merchindiser or end user . . . . 
There are NO books any where, that know what the market is going to do or how to make a quick buck  (or a buck in general).
I find it funny how many commodity books always look back, at what the market did, for examples ~ makeing it seem elementry. Hind sight is always 20/20 . . . .  .
Working with a couple good elevators, to start with, is about the best approch to Marketing a growers crop.
There are several very good University publications to help farmers Market their grain, for free.
I can't locate the link right now, but, if I recall, Ohio state or Iowa state, has a very good one.
If you want to get into speculating, the elevator likely can help with that also . . . . .
Lot's of basic to indepth questions can be answered on this forum also.
Proceed carefully and good luck.