Combining cutting-edge neuroscience with the latest discoveries on the human microbiome, a practical guide in the tradition of The Second Brain, and The Good Gut that conclusively demonstrates the inextricable, biological link between mind and the digestive system.

We have all experienced the connection between our mind and our gut--the decision we made because it "felt right"; the butterflies in our stomach before a big meeting; the anxious stomach rumbling we get when we're stressed out. While the dialogue between the gut and the brain has been recognized by...