This book describes a radical shift in the study of economic science, in which arguing with words was replaced by reasoning with mathematical models. During the last two centuries, the way economic science is done has changed radically: it has become a social science based on mathematical models in place of words. This book describes and analyses that change -- both historically and philosophically -- using a series of case studies to illuminate the nature and the implications of these changes. This book is for people who wants to understand how economics works from the inside out. It will be of interest to economists and science studies scholars. It also aims at a wider readership in the public intellectual sphere, building on the current interest in all things economic and on the recent failure of the so-called economic model, which has shaped our beliefs and the world we live in.