Members of fraternal orders and their wives have carved and embroidered lodge regalia and ritual props that can befuddle outsiders. Curators, historians and dealers are decoding motifs on these objects, which often surface on the market as lodges close.

“The Badge of a Freemason: Masonic Aprons From the Scottish Rite Masonic Museum & Library,” written by Aimee E. Newell, director of collections at the Scottish Rite Masonic Museum & Library in Lexington, Mass., analyzes the textiles that members tie around their waists for lodge ceremonies. These leather and fabric squares are printed, painted, sewn and beaded with images including columns, stone archways, candelabra, burning bushes, construction tools, beehives and disembodied eyes, all symbolizing different virtues and aspirations. The museum purchased a few of the aprons in the last year. (They typically sell for a few hundred dollars each.)

Ms. Newell has identified the apronmakers, sellers and past owners, including a Union soldier who most likely stole his apron from a North Carolina lodge during the Civil War. Little other scholarship has been published about the Freemasons’ decorative arts, she said, and curators outside the Scottish Rite museum, worried that lodge members might be offended, sometimes shy away from displaying the pieces.

“There’s so much out there that’s still ripe for study,” she said.

“As Above, So Below: Art of the American Fraternal Society, 1850-1930” (University of Texas Press), by the art historian Lynne Adele and the folk art dealer and collector Bruce Lee Webb, explores gear used by groups including the Odd Fellows and the Modern Woodmen of America. Ms. Adele and Mr. Webb studied markings and mottos on gravestones, silk banners, furniture, lodge murals and sequined velvet costumes.