Reddit mentions of How to Tune and Modify Automotive Engine Management Systems - All New Edition: Upgrade Your Engine to Increase Horsepowe (Motorbooks Workshop)

I originally tried the same thing (googling everything) but trying to find all the information I was looking for in one place was next to impossible. Plus you have so many contradicting views on how to go about tuning...etc.

Engine Management: Advanced Tuning by Greg banish. Its a little older (written in 2007) but still covers all the basics you will need.

http://www.amazon.com/Engine-Management-Advanced-Greg-Banish/dp/1932494421/ref=sr_1_1?s=books&ie=UTF8&qid=1416614952&sr=1-1&keywords=engine+management+advanced+tuning

Automotive engine management systems by Jeff Heartman. This book came out in 2013 (i believe) and deals a lot with volumetric efficiency (VE) based engine management systems (like the AEM infinity). This book was the first one I read and it really gives you a good understanding of things. Its much longer then the book above, but seeing as how it goes into greater depth and more aspects of tuning its worth the read.

http://www.amazon.com/Modify-Automotive-Engine-Management-Systems/dp/0760343454/ref=sr_1_1?s=books&ie=UTF8&qid=1416615138&sr=1-1&keywords=automotive+engine+management+systems

Other honourable mentions:

Maximum boost by Corky bell (the book is a bit older, but its really well written and interesting)

"How to build" Max-Performance Mitsubishi 4G63 engines, by Robert Bowen (and Robert Garcia of Road Race Engineering RRE)

Engine Airflow by Harold Bettes