At the end of October 1985 a group of friends gathered at the Scuola Normale Superiore, Pisa, to celebrate Gian Carlo Wick's seventy-fifth birthday. They came from near and far to talk physics with him as they had been doing for so many years. And they talked about theory and experiments as they knew that Gian Carlo had always thought that these two sides of physics should never be separated. We dedicate the papers that were presented at the meeting to a dear friend from whose wisdom and knowledge we all profited.