The Global Address List (GAL) is a directory service within email systems, particularly in organizations using platforms like Microsoft Exchange. It contains contact information for all users, groups, and resources within the organization, making it easier for employees to find and connect with one another. The GAL is automatically updated as new users are added or existing ones are modified. It typically includes details such as names, email addresses, phone numbers, and job titles, allowing for efficient communication and collaboration among team members in a corporate environment.