This series contains handwritten and typewritten letters, notes, cards, and facsimiles, arranged chronologically. Most of the letters concern invitations to speak, attend a symposium, or contribute to a publication. Other topics are departmental or inter-university matters, requests to or from other laboratories for clones, and exchanges of opinions on editorial or ethics matters. In these communications, Dr. Varmus is a highly critical reader and writer whose comments are highly valued. Items listed as restricted were transferred from the correspondence files to separate containers.