Marquis Who's Who on the Web is a comprehensive collection of biographies detailing personal and professional facts about some of the world's most accomplished individuals. Biographies in the database include high achievers from all fields of endeavour; comprising government, science, technology and entertainment, the arts, business and sport.

Marquis's biographical volumes have been printed for over 100 years but the new online version has some features that distinguish it from the print editions. The online version is updated daily and allows real-time access. Another helpful function in the online edition is the targeted searching which allows entries to be searched by name, occupation, gender, or geographic location.
The database includes around 1.4 million entries from 21 biographical dictionaries published by Marquis. In most cases listees furnish, update and proofread their own biographies, ensuring that information in the website is reliable and accurate.