The gatherings in the Stein home "brought together confluences of talent and thinking that would help define modernism in literature and art". Dedicated attendees included Pablo Picasso, Ernest Hemingway, F. Scott Fitzgerald, Sinclair Lewis, Ezra Pound, Gavin Williamson, Thornton Wilder, Sherwood Anderson, Francis Cyril Rose, René Crevel, Élisabeth de Gramont, Francis Picabia, Claribel Cone, Mildred Aldrich, Carl Van Vechten and Henri Matisse. Saturday evenings had been set as the fixed day and time for formal congregation so Stein could work at her writing uninterrupted by impromptu visitors. It was Stein's partner Alice who became the de facto hostess for the wives and girlfriends of the artists in attendance, who met in a separate room.
Upon the birth of his son, frequent attender Ernest Hemingway asked Stein to be the godmother of his child. During the summer of 1931, Stein advised the young composer and writer Paul Bowles to go to Tangier, where she and Alice had vacationed.
Gertrude herself attributed the beginnings of the Saturday evening salons to Matisse, as
[m]ore and more frequently, people began visiting to see the Matisse paintings—and the Cézannes: "Matisse brought people, everybody brought somebody, and they came at any time and it began to be a nuisance, and it was in this way that Saturday evenings began."
Among Picasso's acquaintances who frequented the Saturday evenings were: Fernande Olivier (Picasso's mistress), Georges Braque (artist), André Derain (artist), Max Jacob (poet), Guillaume Apollinaire (poet), Marie Laurencin (artist, and Apollinaire's mistress), Henri Rousseau (painter), and Joseph Stella.
While Stein has been credited with inventing the term "Lost Generation" for those whose defining moment in time and coming of age had been World War I and its aftermath, at least three versions of the story that led to the phrase are on record, two by Ernest Hemingway and one by Gertrude Stein.