I wrote the Age of Addition to explain why addiction has become so widespread, conspicuous, and varied. When I entered the field in the 1970s, as a doctoral student studying opiate history, “addiction” referred to drugs like heroin. By the 2010s it also referred to compulsive overeating, sugar consumption, machine gambling, social-media use, internet pornography, shopping, and habitual tanning.Though behavioral addictions remain controversial, they are, at a minimum, social facts. When I told people that I was writing an updated history of addiction, they said without prompting that I had to include kids glued to their smartphones. What had once been a peripheral nuisance had become a real worry, given the dangers of distracted driving and reports of increased bullying, anxiety, and academic failure among heavy users.I knew something about addictive products. In 2001 I published Forces of Habit, a global history of psychoactive drug use, commerce, and regulation that went beyond my early work on opiates. Over the next seventeen years I became convinced, thanks to anthropologists like Natasha Schüll and journalists like Michael Moss, that drugs were not the only things with drug-like effects. Mesmerizing video slots and foods loaded with sugar, salt, and fat could also do the trick. Psychologists like Bart Hoebel and neuroscientists like Nora Volkow made similar arguments. So did behavioral economists like George Akerlof and Robert Shiller, who showed how corporations used habituating, brain-rewarding products to “phish for phools.”When I joined the addiction-research peloton I found myself pedaling alongside other historians. One was the late John Burnham, author of Bad Habits: Drinking, Smoking, Taking Drugs, Gambling, Sexual Misbehavior, and Swearing in American History (1993). Burnham’s brief was that the vices of the Victorian male underworld had gone mainstream. Repeal of Prohibition, World War II, consumerism, the upheavals of the long 1960s, and countercultural and libertarian activists had undermined the crumbling façade of traditional morality.Burnham’s book appeared in 1993, before processed foods and digital technologies featured in discussions of addiction. Seeing a chance to update and globalize his pioneering study, I cast The Age of Addiction as a sequel to Burnham’s Bad Habits as well as to my own Forces of Habit.Injecting neuroscience into world history and arguing that an emerging economic system cuts across cultural differences raised some academic eyebrows. Against this, foreign journalists immediately grasp limbic capitalism when they interview me. “Hey, that’s us too.” Limbic Capitalism almost became the book’s main title, some editors preferring its edginess. Familiarity with brain regions being less universal than awareness of addictions, the current title won out.