"Who's Who" refers to a directory or list of notable or influential people in a field or society. It also describes an event or group packed with big names, a who's who of the scene.
You may have read that I went to M.I.T. In 1982 I filled out a Who's Who survey with joking responses, and they never bothered to check the facts. Chevy Chase
I've played with all of the heavyweights in the modern jazz, progressive jazz movement. I've been fortunate enough to play with them, a who's who. All of those guys, I've been fortunate enough to have performed with. Sonny Rollins
I was 82 years old before Who's Who thought I was enough of a big shot to do a piece on me. Joseph Barbera
Kissing could have begun as a way of sniffing out who's who. From a whiff to a kiss was just a short trip across the face. Joshua Foer
I go to gyms quite a bit, martial arts gyms, MMA gyms. I try to train with the best people, with who's who in the martial arts, just to keep myself sharp. Michael Jai White
Adrian Room, Naming Names: Stories of Pseudonyms and Name Changes, with a Who's Who, Routledge & Kegan Paul, 1981, p. 125. At age 20, he emigrated to America, first to New York, as a bookseller, and then to San Francisco. Source: Internet