Tribe

Sebastian Junger's 2016 book arguing that humans are wired for tribal belonging — shared purpose, mutual obligation, facing adversity together — and that modern affluent individualistic society fails to provide these conditions, producing depression, PTSD, and purposelessness.

Explains why soldiers miss war — not the killing but the belonging, the clarity of purpose, the mutual dependence — and argues that the absence of these tribal conditions in modern society is the primary driver of mental health dysfunction, making community design a public health issue.