In PLEASED TO MEET ME: Genes, Germs, and the Curious Forces That Make Us Who We Are (published by National Geographic) research scientist Bill Sullivan offers a groundbreaking new window into how genetics, epigenetics and microbes work with our environment to make us who we are. Sullivan, a professor of pharmacology and microbiology at Indiana University School of Medicine, draws on cutting-edge research to illuminate how our genes not only dictate our physical traits but can also have an enormous influence on our personality and behavior.

With wit and humor, Sullivan deconstructs provocative studies suggesting that certain genes influence whether someone is a liberal or conservative, violent or timid, lean or obese. But genetic makeup, he explains, is only part of the picture. Through a process called epigenetics, the environment can actually modify our DNA, which may explain how the behavior of our parents — for example, our mother’s behavior during pregnancy or whether our father was a smoker — can play a wide-ranging role in obesity, depression, anxiety and more.

Sullivan also examines recent studies regarding how our microbiota — the trillions of microbes living inside our gut — can affect our behavior and mood. The book draws from the latest psychology research to reveal why and how our brain can trick us into performing irrational behaviors or actions detrimental to our well-being and society. It also explains why people with opposing points of view struggle to convince one another to change their minds.