Multiple object tracking (MOT) involves localizing and identifying multiple moving objects over time using video input. MOT has various applications including human-computer interaction, surveillance, and medical imaging. It allows too many detected objects to be matched across frames and tracks objects even if detection fails in some frames. However, challenges include implementing real-time tracking due to batch-based algorithms and solving identity switches and fragmentation when detections are missed. Common MOT methods include Faster R-CNN for detection, Kalman filters for prediction, CNNs for appearance features, and the Hungarian algorithm for data association and tracking.