We describe the conceptual architecture of a Personalized Information Environment or "PIE". A PIE allows unified, highly customizable access to distributed information resources by providing users the tools to compose personalized collections from a palette of information resources. The architecture also provides for the efficient "exchange" of inter-resource metainformation like collection statistics in order to maximize retrieval effectiveness. This paper includes the enunciation of the user-centered PIE vision, an architectural requirements specification, and an architectural description that meets the specification and supports the vision. We also describe our current implementation and research efforts conducted within the PIE framework. In 1945, Vannevar Bush [2] first described an information environment that he felt was bordering on the unmanageable, with information users awash in research results and scholarly communication and few usable mechanisms to organize them....