Early years: 1845–1865
Post-Civil War era: 1866–1899
Early 20th century: 1898–1945
Post-World War II: 1946–1977
Modern: 1978–present
References
Notes Further reading * * * *Costello, Augustine E. ''Our Police Protectors: History of the New York Police from the Earliest Period to the Present Time''. New York: A.E. Costello, 1885. *Hickey, John J. ''Our Police Guardians: History of the Police Department of the City of New York, and the Policing of Same for the Past One Hundred Years''. New York: John J. Hickey, 1925.External links