This document provides an overview of MOOCs (Massive Open Online Courses). It defines MOOCs as online courses that are open to unlimited participation, have no defined start/end dates, and generally offer no credit or formal certification. The document traces the history and evolution of MOOCs, from their origins in 2008 to the emergence of different types like cMOOCs and xMOOCs. It also describes how MOOCs work, involving video lectures, assessments, discussion forums, and other interactive elements.