Rationality of science was the topic of two conferences (held in 1988 and 1989) organized by the Department of Philosophy of Science, Institute of Philosophy, Jagiellonian University. Both conferences included a small group of invited speakers. This book contains a selection of papers presented there. It is intended mainly for specialists in the philosophy of science and scientists interested in philosophy. Students and especially postgraduate students would also benefit from reading it. The first conference, 'Popper, Polanyi and the Notion of Rationality', was held from 1 to 5 October 1988 in Janowice. The second conference, 'The Aim and Rationality of Science', was held in Cracow at the Jagiellonian Univer­ sity, from 4-10 June 1989. The topics of