[About a year ago Professor E. G. Boring wrote to suggest a symposium on operationism and appended a few questions which he said he would like to have answered. The Editor welcomed the idea and invited a number of persons interested in operationism to take part in the symposium. They were sent Professor Boring's questions and asked to add questions of their own to the list. Professors E. G. Boring, P. W. Bridgman, Herbert Feigl, Harold Israel, Carroll C. Pratt and B. F. Skinner accepted the invitation and submitted additional questions. The complete list was then sent to each participant with instructions to write on any or all of the questions. When the galley proof was ready, all of it was sent to each person with the request that he write a short rebuttal. All but one participant consented. These replies, which are more than rebuttals, follow the main articles under the title "Rejoinders and Second Thoughts."