Collection of research and information gathered by Douglas Frey, an architectural historian and restoration contractor while working on his 2010 publication Marietta, the Gem City of Georgia: A Celebration of Its Homes - A Portrait of Its People. The work includes photographs by Jim DiVitale and was published by Cobb Landmarks and Historical Society, Inc. The collection includes materials related to information about historic districts in Atlanta and the surrounding area; historic homes and sites located in Marietta, including Frey's own home, the "Trammell House"; information for Marietta History Tours; and historic Marietta plats & maps.