Role-based approaches are emerging technologies in information system design and implementation. Roles have been acknowledged and applied in many fields for many years. Considering their increasing importance and applications in the development of various information systems, this paper intends to: 1) Survey the literature relevant to role mechanisms and role-based systems in different fields and point out their motivations and contributions; 2) Classify roles in such different contexts as modeling, designing, management, and collaboration; 3) Identify the commonalities and differences among roles in different fields; and 4) Point out the challenges, benefits, and future research areas of role-based systems. Keywords Information Systems, Agent Systems, Role, Role Concept, Role Mechanism.