The papers in Folders 19-21, which concern 70th and 80th birthday celebrations provide similar insight into Eilenberg's later years and suggest the esteem with which he was held by a wide circle (as do commemorative papers delivered in Eilenberg's honor by math colleagues in Box 7, Folders 21-22). Organized by art dealer and friend Peter Marks, these birthday celebration documents also illustrate the characteristic way in which Eilenberg's professional contacts in the art and math worlds often factored significantly in his personal life too.