For the Symposium organised during the first session of ISTA (Bonn 1980), Eugenio Barba asked the guests to write their comments on what they had seen. The letters by Thomas Bredsdorff, Jean-Jacques Daetwyler, Nicole Revel-Macdonald and Raymonde Temkine, presented here in an English translation, were originally published in La scuola degli attori, edited by Franco Ruffini (Firenze 1981).