Summary records of property transactions, based on block numbers and periods of time, that serve as indexes to (Land Records) in series C205 and C2842. An 1886 law (Ch. 289) directed the clerk of the Baltimore City Superior Court to develop a new plan for indexing land records, subject to the approval of the judges. The resulting block book system was based on the sequential numbering of each block in the city. Initially the block numbers ranged from 1 to 2073, and the indexing system was applied retroactively to include all land records dating back to 1851. Annexations to the city were handled simply by assigning higher block numbers: 2100 to 4199 in 1888 and 4200 to 8491 in 1918. New developments were managed by assigning sequential alphabetical suffixes to the base block number. Block numbers can be obtained from (Block Maps) in series C2845 and C2837. The records are first grouped by periods of time, such as 1851-1886 or 1967-1976, and then numerically by block number. Entries under each block number provide dates of the transactions, names of the parties involved, types of instruments, locations or addresses of the property, and book and page references to (Land Records). Also available on film in series CM196 and CM1349. Records for the 1918 annex were maintained separately for 1918-1953, as found in (Block Book, New Annex) in series C2840. The series consists of approximately 1624 volumes, each containing an average of 212 pages. In 1989 the clerk's office began to use an electronic version of the Cott indexing system to index land records, and in 2002 switched to the Judicial Information System (JIS).