Documents the academic, military, religious, and writing career of Jesuit priest and Boston College professor William J. Leonard, SJ. Materials include artifacts, correspondence, journals, meeting minutes and reports, notes, photographs, and writings. Leonard's involvement in the liturgical movement is particularly well documented, reflecting his pastoral, practical, and scholarly contributions to the revitalization of liturgy and lay participation in the Catholic Church before, during, and following the Second Vatican Council. The papers also feature Leonard's service as a US Army Chaplain during World War II, when he was stationed in New Guinea and the Philippines. Leonard's Boston College materials cover both his teaching and administrative roles, including his role as Curator of the Liturgy and Life Collection at the John J. Burns Library. The papers document Leonard's personal and priestly formation throughout, including personal correspondence, journals, and photographs.