Annotated reprints and correspondence. Primarily reprints (1921-1960) of Warren Mason's research while at the Applied Mechanics Research Group of Bell Telephone Laboratories, Inc., published in PHYSICAL REVIEW and in the Bell Telephone Laboratories' reprint series and technical publications monographs series. Topics include solid state physics, acoustics, and internal friction. Correspondence (1961-1973) covers Mason's administrative/editorial work with Robert N. Thurston for completion of a series of scientific articles on physical acoustics. Also included is correspondence (1965-1972) from Mason's period as research professor at George Washington University and as visiting professor at Columbia University, Henry Krumb School of Mines.