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.