The clinical entities that comprise acute coronary syndromes (ACS)-ST-segment elevation myocardial infarction (STEMI), non-STEMI, and unstable angina-have been recognized as widespread causes of death and disability for more than a century. Seminal research in the past 50 years has led to important scientific and medical advances in our understanding of ACS. Rapid modernization of the developing world has led to a pandemic of coronary artery disease and its manifestation as ACS, with profound implications for personal, societal, and global health. Epidemiological studies have provided insight into the changing demographics of ACS, and highlighted the importance of modifiable risk factors and adherence to guideline-recommended therapy.