The principals of this enigmatic Rock Hill firm have not been identified, but it is certain that they did not include Alfred D. Gilchrist, a well-known Rock Hill architect who designed many buildings in the Rock Hill and Clover areas and died in 1944. Neither the firm nor its principals appear in the historic directories of the AIA.

Gilchrist and Cook was credited with the design for the Clover (1961) armory. Other known projects include the old 1968 Rock Hill City Hall, on which they served as associate architects to the firm of Sadler and Kent.