Platelets play a critical role in hemostasis and thrombosis. The role of platelets in hemostasis, clinically relevant bleeding resulting from defects and/or deficiencies in platelets and/or platelet components, and the diagnosis of such defects was the subject of a previous recent issue of Seminars in Thrombosis and Hemostasis. 1–13 That platelets are of considerable interest to readers of this journal can also be highlighted by the popularity of a previous review published here,‘‘Platelets: Physiology and Biochemistry. 14 Published in 2005, this article was included in the top-20 most popular article listings from this journal in three separate years, 2005, 2006, and 2007, 15 and was also subsequently awarded one of the inaugural (2009) Eberhard F. Mammen awards for most popular articles. 16

The current issue of Seminars in Thrombosis and Hemostasis is dedicated to the role of platelets in inflammation and cardiovascular disease. The last time we extensively explored this topic was in 2007, 17–30 and much research in the field has progressed since then. The classical role of platelets is to control vascular hemostasis. Once vascular lesions are formed, platelets are recruited to the site of injury, form a microthrombus, and seal the infringement to prevent further blood loss. An uncontrolled vascular platelet activation results in intravascular thrombus formation and disturbance of blood flow, which in turn leads to tissue ischemia and organ dysfunction.