An audit trail is a chronological record that tracks and logs all user activities, system events, and transactions within an information system. This record provides detailed information about who performed an action, what action was taken, when it occurred, and where it took place. Audit trails are essential for ensuring transparency, detecting and preventing insider threats, and maintaining data integrity. They support regulatory compliance by providing evidence of adherence to policies and procedures. In the event of a security incident, audit trails enable thorough investigations and help identify the cause and scope of the breach.