Although several collaborative office systems have been developed recently to provide synchronous communication support for managerial work, they have not capitalized on electronic mail (E‐mail), an existing asynchronous office communication technology widely used by managers. This is because E‐mail technology has yet to incorporate intelligent characteristics and flexibility to support different office functions, which can enable it to adapt to the changing and uncertain environment of managerial work. This article addresses the conceptual and technological issues involved in development of E‐mail to support managerial work with MAIL‐MAN, a knowledge‐based E‐mail system unified with other office applications to model and support managerial work.