Today there are at least 70 border walls: from the US-Mexico border to the 17,000 miles of barbed wire that wall off Bangladesh from India, as well as the five-layer fence between Saudi Arabia and Iraq. Border walls protect us, the argument goes, because they keep danger out. But what if the walls themselves endanger everyone who lives near them - on both sides? In this thoroughly reported, eye-opening work, science journalist Jessica Wapner reveals the unforeseen mental health effects of security walls - including depression and anxiety, despondence, excitability, suicidal ideation, paranoia, and more. Doctors first noticed these conditions proliferating among people who lived along the Berlin Wall, and they gave the overarching affliction a name: wall disease. Wapner builds on this research, following the trail of psychological harm around the world today. Weaving together interviews with those living up against walls and expert testimonies from psychologists, economists, geographers, and other specialists, Wapner explores the growing epidemic of wall disease - and illuminates how neither those "outside" nor "inside" are immune.