The book “What Happened? The Story of the Decline of Society in Iran”, a joint work by Abdolmohammad Kazemipour and Mohsen Goodarzi, explores one of the most critical sociological ruptures in contemporary Iran, namely the structural erosion of “society” and the decline of social solidarity. The main issue of this article is to examine the process through which coherent interpersonal bonds have given way to social isolation and increasing individualism. Relying on empirical evidence, national survey data, historical analyses and experiences from Iran and the world, and theoretical approaches, the authors argue that collective life in Iran, under the influence of macro-structural, political, and economic developments, has suffered a kind of crisis in the reproduction of social capital. In four general sections, this work first explains the fundamental concepts of social capital and then, with a historical-analytical perspective, traces the declining trend of civic participation and the crisis of trust at the micro, meso, and macro levels. The book then paints a multidimensional picture of the causes of social decline, focusing on variables such as ideological shifts, the decline of public morality, the inefficiency of the state institution, economic inequalities, and the consequences of immigration. The ultimate goal of this work, beyond a mere description, is to provide operational solutions for repairing social bonds and reviving civic life. By reviewing and critiquing the main themes of the book, this article attempts to evaluate the contribution of this work to understanding the current challenges of Iranian society and assessing the feasibility of rebuilding social capital.