Edward E. Qian 
Risk Parity Fundamentals [PDF ebook] 

Written by an experienced researcher and portfolio manager who coined the term "risk parity, " this book provides readers with a practical understanding of the risk parity investment approach. It uses fundamental, quantitative, and historical analysis to address the merit of risk parity as well as the practical and underlying aspects of risk parity investing. Requiring no advanced degrees in quantitative fields, the book analyzes risk parity performance from historical periods and more recent market environments.