Ray Dalio is the founder and long time CEO (now Co-Chairman) of his hedge fund Bridgewater. The first 3rd of the book describes his journey through writing and refining these principles over 30 years of operating his company. He had systematized and computerized the analysis and management of their financial portfolio and eventually, Ray figured out that he MUST systematize (and in some ways computerize!) the management system of Bridgewater. Principles is the public version of those principles. Ray does a splendid job in describing varying methods of using the book, reading the book, and integrating the methods into your work and life. It’s approachable to all readers, of all ages, of any discipline or career path. It’s clear, concise, organized, and very pragmatic. This book is now in my Top 10 books, for ANYTHING, and I’ll be sure to share these principles (and as he suggested, the ones modified to fit your personal and professional life) with my children. I recommend this book for essentially anyone in their personal and professional lives who want exposure to what principles are at a minimum but at the other end, for those who want a systematized practice for life and work.