The design and implementation of a conceptual model, CAFE (a Categorization Assistant For E-mail), is described. The model supports the organization, searching, and retrieval of information in e-mail. Three modes are available for satisfying the users' needs in various situations: the Busy mode for intermittent use at times of high stress, the Cool mode for continuous use at the computer, and the Curious mode for sporadic use when exploring and (re-)organizing messages when more time is at hand. The design of the model is motivated partly by the results of a case study of categorization on the computer screen, and partly by a survey of e-mail clients. The case study was inspired by cognitive science theories. The model is related to information seeking theories in electronic environments. In the implementation each mode required using a different technique. The Busy mode uses the text- based Naive Bayesian algorithm, the Cool mode uses e- mail filtering rules, and the Curious mode uses a combination of clustering techniques known as Scatter/Gather.