The Slip: The New York City Street That Changed American Art Forever by Prudence Peiffer:
Kelly met the composer John Cage and his partner, the choreographer and dancer Merce Cunningham, when they stayed for a time at the same Hôtel de Bourgogne in Paris. Kelly was headed to the metro and Cage yelled out to him, “I saw you coming out of the hotel and you look like an American—what do you do?” Kelly answered, “Well, I’m a painter.” Cage had come by Kelly’s room to look at his paintings, and the two kept up a correspondence. Cage and Cunningham gave Kelly “a great feeling that I was doing something that could be important.” It made Kelly impatient to share his new ideas about composition with other artists interested in the same thing. The great paradox of Paris at the time was that the extreme access it offered to artists’ studios was in direct opposition to the insular world of its gallery and museum system.