A telephone directory (also called a telephone book and phone book) is a listing of telephone subscribers in a geographical area or subscribers to services provided by the organization that publishes the directory.

Content

In the case of unlisted numbers, practices as to Caller-ID vary by jurisdiction. Sometimes, the Caller-ID on outbound calls is blank; in other jurisdictions, unlisted numbers still appear, unless the caller dials a blocking code; in still others, the customer may request automatic blocking from the telephone company's service representatives.

In some countries under current rules and practices, mobile phone and Voice over IP listings are not included in telephone directories. Efforts to create cellular directories have met stiff opposition from several fronts, including a significant percentage of subscribers who seek to avoid telemarketers.

In 1991, the U.S. Supreme Court ruled (in Feist v. Rural) that telephone companies do not have a copyright on telephone listings, because copyright protects creativity and not the mere labor of collecting existing information. Within the geographical reach of the Court, the Feist ruling has resulted in the availability of many innovative telephone directory services on CD-ROM and the World Wide Web.

Publication

Telephone directories can be published in hard copy or in electronic form. In the latter case, the directory can be provided as an online service through proprietary terminals or over the Internet, or on physical media such as CD-ROM.

In France, the Minitel videotex system originated as an attempt by France Télécom to rid itself of its paper publishing costs by forcing all telephone users to use Minitel terminals instead.

In Switzerland, most pay phones are now accompanied with electronic telephone directory terminals instead of paper directories, and phone users are charged for each search.

Types

A telephone directory may also be called a phone book or may be known by the color of the paper it is printed on.

• White pages generally indicates personal or alphabetic listings.
• Yellow pages, sometimes called the A2Z, generally indicates a business directory classified by business type or services provided, almost always with paid advertising.

In Ireland it is called the Golden Pages1 and is available in print and online.

• Grey pages, sometimes called a "reverse telephone directory".
• Other colors may have other meanings, depending on a country's customs. Information on government agencies is often printed on blue or green pages.