Who's Who (UK) in the context of "Reference work"

A reference work is a document, such as a paper, book or periodical (or their electronic equivalents), to which one can refer for information. The information is intended to be found quickly when needed. Such works are usually referred to for particular pieces of information, rather than read beginning to end. The writing style used in these works is informative; the authors avoid opinions and the use of the first person, and emphasize facts.

Indices are a common navigation feature in many types of reference works. Many reference works are put together by a team of contributors whose work is coordinated by one or more editors, rather than by an individual author. Updated editions are usually published as needed, in some cases annually, such as Whitaker's Almanack, and Who's Who.

A Who's Who (or Who Is Who) is a reference work consisting of biographical entries of notable people in a particular field. The oldest and best-known is the annual publication Who's Who, a reference work on contemporary prominent people in Britain published annually since 1849.

In addition to legitimate reference works, some Who's Who lists involve the selling of "memberships" in directories that are created online or through instant publishing services, and have been described as scams.