"The need of a comprehensive directory of city departments has long been recognized, but has remained for the present administration to issue the first edition," said Supervisor of the City Record, Peter J. Brady in 1918. Nearly 100 years later, the Official Directory of the City of New York continues to be distributed, and is regarded by many as important documentation of New York City history, reflecting the growth of the City's people and politics over the years.
Every edition of the Green Book includes a history of New York City. However, the Green Book itself can be construed as historically significant. Under the 11-year tenure of one of New York's most notable mayors, Fiorello La Guardia, New York was heralded as "The Greatest City in the World." This logo appeared in the Green Book during his mayoral term and several subsequent administrations. Slogans advertising the sale of war bonds were also featured in 1943. The Green Book is not only an indication of a change in government, but also a change in economy.
Technological advances throughout the century were reflected in the Green Book as they became available to city employees. In 1931, automated dialing service phone numbers (PEnn numbers) were listed in the directory, and in 1965 the contemporary seven-digit phone numbers replaced the PEnn numbers. The Green Book listed fax numbers in the 1989-1990 edition. When the internet became an essential resource of information, internet addresses were added in 1996. In 2003 City Share, the Citywide intranet, posted the first online version of the directory for use by City employees. The Green Book Online was made available in the Spring of 2012 as a searchable, digital application on the internet.
Even this technology-savvy directory needed a modern look after so many years. Starting in 1943, several editions of the Green Book featured a green velvet cover, but that was the extent of its cosmetic change. It was not until the 1990s that it was finally made over. In 1992, the Green Book increased about 20% in size to make reading the directory easier, and to accommodate the growing amount of City information. In 1994, the faded green background took on a darker hue and the gold lettering a brighter shade. Cover features also added in making each Green Book extra special.
Only after the 50th Anniversary of the Green Book did cover features become initiated. 1976 celebrated the bicentennial of the American Revolution, and an official directory of 1775-1776 was compiled by available documents and secondary sources. The 1980s saw covers honoring George Washington, the history of the Brooklyn Bridge, the Statue of Liberty, Bellevue Hospital, and the Manhattan Municipal Building. In the last decade seven covers were introduced, commemorating the NYC Fire and Police Departments, the NYC water supply system, the Harlem Courthouse, and the New York Yankees.
Since 2002, the cover of each edition has explored the theme of New York City as an inspiration for the world's artists. Keith Haring's Statue of Liberty was the featured cover for the 2002-2003 directory and Roy Lichtenstein's I Love Liberty was the featured on the 2003-2004 directory. Third grade students attending the City Hall Academy Day School collaborated on a portrait of the Statue of Liberty for the 2004-2005 edition.
The 2005-2006 Green Book was printed with a saffron cover in tribute to The Gates, Central Park, New York City, the work by Christo and Jeanne-Claude in which Central Park was adorned during February 12-28, 2005 with saffron-colored fabric panels atop 7,503 gates that lined the park's walkways. The 2008-2009 Green Book cover highlights PlaNYC: A Greener, Greater New York, the City's comprehensive plan to make New York a 21st century, sustainable city. The image shows the Statue of Liberty holding a compact fluorescent lamp (CFL) and invites New Yorkers to "Help Make NYC Greener."