Maps of Baltimore City showing block numbers that are used for organizing references to land transactions recorded in (Land Records) of the Superior Court, 1851-1982, and Circuit Court, 1983-. The documents were maintained by the City Department of Public Works and comprise the most complete and best preserved set of records. The maps show the block numbers originally assigned in 1851 and the additional ones after the annexations of 1888 and 1918. Block numbers remain the same regardless of changes in street names or house numbers. The block book maps represent the first step in searching for land records in Baltimore City. They provide the block number for a specific address. The (Block Book) in series CM196, CM197, and CM1349 contain references to (Land Records) in series CM203 and CM1273 for all transactions in each block for specified periods of time. The third step involves a review of the land records themselves.