I recommend "Mastering Bitcoin" by Andreas M. Antonopoulos. It provides great detail on how the Bitcoin network actually works, including the cryptography you need. Work through that and you'll know how blockchain payments work and have a good idea of how the technology can be applied to other areas.

It's available from O'Reily: http://shop.oreilly.com/product/0636920032281.do

Since nobody has mentioned it yet, Andreas Antonopoulos' book, "Mastering Bitcoin," is quite good.

You can build the ePub from source:

https://github.com/bitcoinbook/bitcoinbook

Or get it from oreilly:

http://shop.oreilly.com/product/0636920032281.do

El Narco: http://www.amazon.com/El-Narco-Mexicos-Criminal-Insurgency/d...

Mastering BitCoin: http://shop.oreilly.com/product/0636920032281.do

I learned a lot from Mastering Bitcoin by Andreas M. Antonopoulos (http://shop.oreilly.com/product/0636920032281.do)