Chapter 1: Homogamy And Tribalism: How Our Desire to Belong Can Lead to Extremist Identification.- Chapter 2: Shared Hatred Bringing People Together and Bonding Us.- Chapter 3: Emotional Contagion and Our Relationships: Dealing with the Impact of Extremist Identities with Those We Love.- Chapter 4: "Deplorables": Reciprocal Dehumanization across Party Lines.- Chapter 5: Identity, Extremism, and (De) Radicalization.