Minimizing interruptions to users is a crucial and acknowledged precondition for the adoption of new intelligent technologies such as ubiquitous and proactive computing. This paper takes a step toward achieving a consensus among the numerous existing approaches addressing the challenge posed by interruptions. We start by explicating why interruptions are considered important. We then reveal similarities and differences among the approaches from a cognitive viewpoint. It appears that the approaches draw from different assumptions about human cognition. Some of the approaches contain inconsistencies. The cognitive analysis also inspires directions for future work. Author Keywords Interruptions, intelligent environments, user interfaces. ACM Classification Keywords H5.2. User Interfaces: Theory and methods