Pictured here is Professor MS Slaughter, presumably in his office at Grinnell College.
Notice how this photograph appears to be a more candid shot of Slaughter. His hand appears to be moving and he is not posing for the camera (perhaps the photo was staged this way). Notice also the classical bust (not sure of whom) atop his bookshelf to the left of the photograph. Such seems appropriate for a man dedicated to the Greek and Roman Classics.
FmChrisJones}GrinLibArchive=52 psl1 Moses S. Slaughter - Grinnel.jpg