The American Philosophical Society (APS), on behalf of a coalition of eleven institutions, requests a grant from the National Science Foundation to cover the four-year start-up phase of a new endeavor, the Philadelphia Area Center for the History of Science (PACHS). An important element of what Jefferson called "the course of human events," the histories of science and technology clarify and interpret the sciences, broadly construed, as human endeavors. Though comparatively new additions to the humanities, the histories of science and technology, interdisciplinary by nature, have secured a place within the academy, with at least 23 institutions in the United States alone now offering the Ph.D. in these fields, a robust body of peer reviewed journals, and a significant corpus of monographic literature authored by two or three generations of groundbreaking scholars, from whom younger scholars draw both wisdom and inspiration. As arguably the birthplace of American science, Philadelphia contains resources in this field that are unparalleled in their historical depth as well as breadth. The founding institutions of PACHS are integral to the history of science in America and are consequently the repositories for some of the most important primary sources for the field. Two of the eleven institutions the University of Pennsylvania and Princeton University are home to leading departments in the history of science. Intellectual Merit PACHS will make the collections and scholarly resources of the member institutions and others in the region more broadly available for research in the history of science, technology, medicine, and related fields, creating a synergy that will provide unparalleled opportunities for studying the history of American science in particular. The mission of PACHS will be to promote scholarship in the history of science; encourage the use of the rich research assets of its constituent institutions, particularly in ways that recipients of fellowships from a single institution might have found difficult to pursue because of residency restrictions; provide support for visiting scholars through fellowships, seminars, and other opportunities; encourage better public understanding of the history of science and related disciplines; and provide opportunities for member institutions to collaborate in collection development, fund-raising, and other programs. Broader Impacts The PACHS community will be wide-reaching, encouraging participation from many types of individuals: those who self-identify as historians of science, technology, medicine, and related fields; those whose interdisciplinary scholarship makes access to history of science collections necessary; and others from a broad range of related disciplines who seem likely to find relevant materials in Center repositories and share common interests with Center fellows. The scholarship that PACHS will engender will be shared with the broader academic community and the general public. The PACHS website will be the primary vehicle for disseminating the work of research fellows, and it will also allow public access to virtual exhibitions and educational materials that result from work at the Center. Other programs for the public will include conferences, and special events such as guest lectures and public symposia.