Address book

An address book or a name and address book is a book, or a database used for storing entries, called contacts. Each contact entry usually consists of a few standard fields (for example: first name, last name, company name, address, telephone number, e-mail address, fax number, mobile phone number). Most such systems store the details in alphabetical order of people's names, although in paper-based address books entries can easily end up out of order as the owner inserts details of more individuals or as people move. Many address books use small ring binders that allow adding, removing, and shuffling of pages to make room.

Little black book

The 1953 film Kiss Me, Kate features a musical scene in which Howard Keel's character laments the loss of the social life he enjoyed before marriage, naming numerous female romantic encounters while perusing a miniature black book, which has given rise to the trope of a little black book referring to a list of past or potential sexual partners.

Software address book

Address books can also appear as software designed for this purpose, such as the "Contacts" application included with Apple Inc.'s Mac OS. Simple address books have been incorporated into email software for many years, though more advanced versions have emerged in the 1990s and beyond, and in mobile phones (a SIM card can store entries).

A personal information manager (PIM) integrates an address book, calendar, task list, and sometimes other features.

Entries can be imported and exported from the software to transfer them between programs or computers. The common file formats for these operations are:

LDIF (*.ldif, *.ldi)

Tab delimited (*.tab, *.txt)

Comma-separated (*.csv)

vCard (*.vcf)

Individual entries are frequently transferred as vCards (*.vcf), which are comparable to physical business cards. Some software applications like Lotus Notes and Open Contacts can handle a vCard file containing multiple vCard records.