The Tokyo Metropolitan Library (東京都立図書館) was opened after taking over collections from Hibiya Library in 1973. The Library holds a large collection of books, periodicals, and audio-visual materials. The Central Branch holds 240,000 items, including over 40,000 documents pertaining to the history of Tokyo. (Some of those materials are over 400 years old). Total holdings of the Metropolitan Library, including information materials in storage, are estimated at about 1,800,000 items.
Books are divided by subject: Reference, Social Sciences, Humanities, Natural Science. In addition the library just opened a "regional history research center."
With its easy accessibility, central location, and open stacks, the Tokyo Metropolitan Library is a favorite research site for foreign visitors and Tokyo residents alike.