The Telephone Directories collection documents the names and occupations of citizens and companies, as well as their phone numbers, along the Eastern Shore of Maryland and Delaware, in 1923, 1925, and 1938.

The directories were produced by the Diamond State Telephone Co. and the Chesapeake and Potomac Telephone Co. The Diamond State Telephone Co. founded in 1897, it became a part of the Bell System in 1905. When the AT&T breakup occurred in 1984, DST became managed by the Regional Bell Operating Company Bell Atlantic. In 1994, Bell Atlantic chose to "unify" its brand by legally renaming all of its telephone companies — including Diamond State Telephone to "Bell Atlantic – Delaware, Inc". After the 2000 merger with GTE, Bell Atlantic – Delaware, Inc. became known as Verizon Delaware, Inc., and later Verizon Delaware LLC.
The C&P Telephone Company of Maryland was founded in 1884 as The Chesapeake and Potomac Telephone Company of Baltimore City. It changed its name to The Chesapeake and Potomac Telephone Company of Maryland on January 3, 1956, and the corporate name at this point changed to C&P Telephone of Maryland. After AT&T's 1969 corporate identity overhaul, which included the famous Saul Bass Bell logo, all four companies' names were shortened to C&P Telephone on marketing materials, bills, vehicles, etc.In 1984, when the Bell System was divided into the Regional Bell Operating Companies, or "Baby Bells", the C&P Telephone companies became part of Bell Atlantic. In 1994, Bell Atlantic renamed all of its operating companies. C&P Telephone was renamed: ell Atlantic – Maryland, Inc. After Bell Atlantic's merger with GTE in 2000, the system was renamed Verizon, and so were its Bell Operating Companies. After AT&T's 1969 corporate identity overhaul, which included the famous Saul Bass Bell logo, all four companies' names were shortened to C&P Telephone on marketing materials, bills, vehicles, etc.