This paper presents an overview of research at Rochester addressing problems in developing large-scale plans in complex worlds. The work can be divided into three general areas. We address representational issues by developing new representations of actions and plans that increase the expressiveness of plan representations, especially in dealing with external events and interacting overlapping actions. We address efficiency issues by developing a set of temporal reasoning algorithms for the efficient handling of very large-scale temporal databases. And finally, we address the problem of developing plans in the real world by defining a model of mixed-initiative planning using an interactive dialogue-based model of plan management. By viewing the human as an essential part of the planning process, we dramatically change the problems that are important for the ultimate successful application of planning technology.