An address book or a name and address book (NAB) 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.
A related term that has entered the popular lexicon is little black book (or simply black book). Such books are used as dating guides, listing people who the owner has dated in the past or hopes to in the future. More explicit variations are guides for sexual encounters. It is unclear how prevalent this is in practice or when it originated, though such books have been mentioned in many pieces of popular entertainment. For example, the 1953 film version of 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 whilst perusing a miniature black book. More recently, the mid-2000s Guinness Brewmasters advertising campaign features the "little black book" as an invention of one of the brewmasters.
