Who's Who is a reference work. It is a book, and also a CD-ROM and a website, giving information on influential people from around the world. Published annually as a book since 1849, it lists people who influence British life, according to its editors. Entries include notable figures from government, politics, academia, business, sport and the arts. Who's Who 2022 is the 174th edition and includes more than 33,000 people. The book is the original Who's Who book and "the pioneer work of its type". The book is an origin of the expression "who's who" used in a wider sense. History Who's Who has been published since 1849. It was originally published by Baily Brothers. Since 1897, it has been published by A & C Black. It has been published in New York by the Macmillan Company and by St. Martin's Press. From 1849 to 1850, Who's Who was edited by Henry Robert Addison, from 1851 to 1864 by Charles Henry Oakes, from 1865 by William John Lawson and from 1897 to 1899 by Douglas Brooke Wheelton Sladen. Subsequent editions do not disclose the identity of their editor. Originally, it merely provided lists of the names of notable people, for example all members of parliament and all bishops. Beginning with the 1897 edition, it listed people alphabetically and provided fuller biographical details. Cedric A Larson said that Who's Who in 1849 was not biographical. Who's Who turned into a biographical dictionary in 1897. In 1963 and 1975, William L Rivers wrote that Who's Who includes biographical information. In 1973, a spinoff version, called The Academic Who's Who, was released by the same publisher. Both the first edition, published in 1973, and the second edition, published in 1975, were published by Adam & Charles Black in London. The first US edition was published by Bowker in New York, and the second by Gale Research in Detroit. The second edition contained biographies of almost seven thousand academics. Who's Who 1897–1996 was published on CD-ROM and was awarded the McColvin Medal. Who's Who 1897–1998 was also published on CD-ROM. Who's Who was included in KnowUK from 1999. Who's Who 2005 was included in Xreferplus. The Who's Who & Who Was Who website (ukwhoswho.com) is dated from 2007 onwards. Who's Who continues to be published annually in hard copy. A history of Who's Who was published to coincide with the 150th edition in 1998.