Each week of Chautauqua's nine week season is given a lecture theme and with a lecture held weekdays during the season at 10:45 a.m., the Amphitheater stage becomes a platform for distinguished scientists, authors, educators and other experts in such fields as national and international affairs, arts and humanities, business and the environment. Ideas and opinions are exchanged in an open, challenging atmosphere, and Chautauqua's knowledgeable audiences have the opportunity to participate in question-and-answer sessions at the conclusion of the lectures.