"Popular science has been overrun in recent years with guides to the microbiome — the aggregate genetic substance of all the microorganisms living in and on our bodies. Beyond a naive understanding of bacteria as uniformly pathogenic, titles like The Microbiome Solution: A Radical New Way to Heal Your Body From the Inside Out (by Georgetown gastroenterologist Robynne Chutkan) and The Good Gut: Taking Control of Your Weight, Your Mood and Your Long-Term Health (by Stanford microbiologists Justin and Erica Sonnenberg) have popularized a conceptual turn toward recognizing bacteria as potentially beneficial. These handbooks are particularly attentive to microorganisms located in our gastrointestinal tracts as arbiters of individual wellness."