Collection consists of a diary of written by Mary S. Sabin, the sister of the noted scientist Florence Sabin. Born in Central City, Colorado in 1969, Sabin moved to Denver with her family as a child. She later attended Smith College, graduating in 1891. After graduation Sabin was offered an assistantship in the Astronomy Department at Smith. Refusing the offer, Sabin returned to Denver to accept a teaching position in mathematics at East High School. She taught at East High until her retirement in 1931. In addition to her career as a teacher Sabin was also an avid naturalist and one of the founders of the Colorado Mountain Club.