This document discusses various systems for classifying malocclusion. It begins by defining malocclusion and explaining the need for classification systems. It then covers Angle's original 1899 classification system, which categorizes malocclusions based on molar relationships. Several modifications to Angle's system are also presented, including the British Standard classification of incisor relationships. Other classification systems discussed include Andrew's Six Keys, skeletal classification, canine classification, Simon's classification, and Ackerman and Proffit's classification.