Jean-Paul Sartre was working furiously on his second play, Les Mouches (The Flies), while finishing his major philosophy treatise, L’Être et le néant (Being and Nothingness). Jean Paulhan had convinced Gallimard to publish the 700-page essay even if the commercial prospects were extremely limited. However, three weeks after it came out in early August, sales took off. Gallimard was intrigued to see so many women buying L’Être et le néant. It turned out that since the book weighed exactly one kilogram, people were simply using it as a weight, as the usual copper weights had disappeared to be sold on the black market or melted down to make ammunition.