Written by Stephen Porges, this book is a comprehensive review of the parts of our brain that make up the Polyvagal System, which we can think of as our "Social Engagement System" - the neurophysiological foundations of human emotions, attachment, communication and self-regulation. These are the functions that set us apart from other mammals, and which evolved to support the survival of clans of hunter gatherers in challenging conditions.
The Polyvagal System is part of our unconscious mind, and trauma in our early years shuts down and alters its healthy functioning. The book is a collection of academic papers that have been edited and assembled into five main sections, and it is not easy reading.
Instead of buying the book from Amazon, I prefer to borrow it from my local library.
And you can also enjoy reading the informative and helpful Introduction to the book, written by Bessel Van Der Kolk.
Dr. Arielle Schwartz gives an easy-to-understand description of how the polyvagal system functions in her article about getting unstuck from PTSD.
See also this interview with Stephen Porges
And see our article about measuring Heart Rate Variability.