Lamb was a native of Scotland; Rich was born in Beverly, Massachusetts, and attended Dartmouth College.
Not much is known of their training, but various sources indicate that Lamb generally handled the firm's business side and Rich was the designer.
Most of the firm's projects were located within commuting distance of Manhattan, with a cluster in New Hampshire, especially at Dartmouth College.
Art historian Vincent J. Scully Jr. noted the vitality of their designs in his 1971 book, The Shingle Style and the Stick Style: Architectural Theory and Design From Richardson to the Origins of Wright (Yale University Press, 1955, revised 1971).
One of their earliest commissions was Henderson Place, a tight-knit group of two dozen houses built in 1882 and located at 86th Street and East End Avenue in Manhattan.