Reddit reviews Advanced Rhythmic Concepts for Guitar; Foreword By Alex Machacek: (An in-depth study on Metric Modulation, Polyrhythms and Polymeters)

They are both brilliant and will last a lifetime, I've had them for around 5 years and they still blow my mind, and keep me learning.

Some others I own and think a great are:

[Creative Guitar 1 and 2 by Guthrie Govan] ( http://www.amazon.com/Guthrie-Govan/e/B0034Q44JU/ref=ntt_athr_dp_pel_pop_1) In my opinion the best guitarist around. He has a mastery over the guitar at a level I have never seen! These books are excellent a written in a ways that enjoyable and easy to understand

[Single Note Soloing, Volume 1] (http://www.amazon.com/Jazz-Guitar-Single-Soloing-Volume/dp/0769209726/ref=pd_sim_b_2?ie=UTF8&refRID=0MRB4A99W8P09SX6GMQG) and [Volume 2] (http://www.amazon.com/Jazz-Guitar-Single-Soloing-Volume/dp/0739053841/ref=pd_sim_b_2?ie=UTF8&refRID=1GGV91GVW1H6MM5AQ6C0) by Ted Greene. Excellent for jazz soloing.

[The Jazz Theory Book by Mark Levine] ( http://www.amazon.com/Jazz-Theory-Book-Mark-Levine/dp/1883217040/ref=pd_sim_b_17?ie=UTF8&refRID=1FP5R211R7V7ZDP5Q4GT) THE book on jazz, this is without a doubt a must own!

If you want to get really deep and crazy take a look at the Scott McGill books:

[Scott McGill] (http://www.amazon.com/Scott-McGill/e/B00J36EZ58/ref=ntt_athr_dp_pel_1)

And lastly for an insane look at rhythms [Advance Rhythmic Concepts for Guitars by Jan Rivera] (http://www.amazon.com/Advanced-Rhythmic-Concepts-Foreword-Machacek/dp/0615979831/ref=pd_sim_b_2?ie=UTF8&refRID=0J05GGH3PGDQRWPRB298) Metric Modulations, Polyrhythms and Polymeters galore! I feel with most guitarists rhythm is often overlooked and getting your rhythmic playing down separates the men from the boys. It's amazing how good rhythm can make the simplest of solos mind melting.

Advanced Rhythmic Concepts for Guitar by Jan Rivera covers metric modulation, polyrhythms and polymeters.