Subscriber names are generally listed in alphabetical order, together with their postal or street address and telephone number. Every subscriber in the geographical coverage area is usually listed, but subscribers may request the exclusion of their number from the directory, often for a fee. Their number is then said to be "unlisted" (American English), "ex-directory" (British English) or "private" (Australia and New Zealand).

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 the US, 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.

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 renting a Minitel terminal to all telephone users. However, France Télécom continues to give hard copies to its subscribers.

In Iceland, directories are published in hard copy and there is also an online directory at Ja.is providing various related services.

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.

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

A telephone directory may also provide instructions about how to use the telephone service in the local area, may give important numbers for emergency services, utilities, hospitals, doctors and organizations who can provide support in times of personal crisis. It may also have civil defense or emergency management information. There may be transit maps, postal code guides, or stadium seating charts, as well as advertising.