IPAC exists to carry out large, data-intensive processing tasks of critical importance to NASA's long-wavelength astrophysics program, and to provide scientific expertise on those projects to the broad scientific community. The IPAC philosophy is to work on projects that are too large in terms of computational hardware, software, or operational resources to be handled by a single university group, and which the community has identified as having a high scientific priority. Critical to the proper execution of all programs at IPAC is a staff of active researchers who can guide the development of those tasks and subsequently assist other astronomers in using the final products. IPAC activities are led by scientists who combine an overall understanding of the goals of a project with technical knowledge of how those goals can be achieved in a timely and cost-effective manner. Smaller projects are undertaken only if they are particularly synergistic with the IPAC mission or if they can be carried out more economically at IPAC than elsewhere.