A prolific and decorated scholar, a talented and hard-working administrator, and an encouraging and supportive mentor, Frederick Mosteller was one of the leading statisticians of the twentieth century. He wrote and edited over 50 books and published nearly 350 papers. He was instrumental in establishing the Statistics Department at Harvard University, where he taught and administered for over 50 years. Mosteller contributed to numerous studies in wide-ranging fields from social sciences to healthcare to education. His work was widely recognized and hailed as influential, both in its breadth and content. He was celebrated as both a scholar and leader in statistics. The Mosteller Papers are an important source for scholars in multiple disciplines, both for those interested in particular ground-breaking studies, and for those interested in the history of statistics and statistical methodology. The Mosteller Papers provide an interesting insight into the work of Frederick Mosteller. Including correspondence, manuscripts, printed matter, and awards and certificates, the collection is comprised of twenty linear feet of material from Mosteller's professional life. The collection contains expansive records of Mosteller's time at Harvard University, as a scholar, a teacher, and an administrator. It includes insight into his thoughts, his works, and his activities. Throughout his long and illustrative career, Mosteller collaborated with a wide variety of experts in diverse fields, and contributed to numerous committees and studies, both within academia and in a wider milieu, and the papers attest to that.