Hi man.
A very good book to learn some Jazz is “The Jazz Theory Book by Mark Levine”.
It has simple concepts, chapter for chapter, It explains step by step from Theory, Improvisation, Chords, Scales, Reharmonization and more.
http://www.amazon.com/Jazz-Theory-Book-Mark-Levine/dp/1883217040
P.S. Sorry If my English is bad, but I’m not English, I’m Italian 🙂