Pt. 1. Those who play. Why do perfectly normal people become raving lunatics online? -- Why do people cheat, hack, and peek at strategy guides? -- Why are fanboys and fangirls so ready for a fight? -- Why do we get nostalgic about good old games? -- Pt. 2. Those who make. How do games get us to keep score and compete? -- How do games get us to grind, complete side quests, and chase achievements? -- How do developers keep us so excited about new loot? -- 3. Those who sell. How do games make us feel immersed in imaginary worlds? -- Why do we go crazy for digital game sales? -- How do games and apps get you with in-game purchases? -- How do games keep players playing? -- How do games get players to market each other? -- Pt. 4. The games themselves. Do we shape our in-game avatars or do they shape us? -- Why do we like violent games so much? And should we be worried that we do? -- Do video games make you smarter? -- Conclusion: Where do psychology and video games go from here?