Cardiogenic shock (CGS) is common and highly morbid. According to the National Inpatient Sample, there are more than 100,000 cases per year, and 30-day mortality approaches 50% despite improvements in critical care practices and novel mechanical therapies targeted at restoring normal hemodynamics. This issue aims to enhance clinicians’ understanding of CGS, and this review specifically focuses on the underlying pathophysiology. We examine the definition and etiologies of CGS, approaches to risk assessment, and the pressure-volume loop framework that is the foundation for conceptualizing ventricular mechanics, ventricular-vascular interactions, and the derangements observed in CGS. This overview will also contextualize subsequent chapters that discuss nuances of CGS encountered in particular scenarios (ie, post-myocardial infraction, acutely decompensated chronic heart failure, post-cardiac surgery), address pharmacological and mechanical treatments for CGS, and review CGS in a case-based format.