This document discusses various aspects of orthodontic anchorage. It defines anchorage and provides classifications including according to the manner of force application, the jaws involved, and the site of anchorage. Biological aspects are covered such as factors affecting an individual tooth's anchorage value like the number, shape, and length of roots. Mechanical aspects include using force couples to restrict unwanted tooth movement. Different anchorage reinforcement techniques are presented such as extraoral appliances, implants, and temporary anchorage devices.