As usual, when preparing a new edition, we have made many small changes to improve clarity of exposition and to update the text both for recent economics events and for relevant advances in the literature. But this time we have focused on one particular addition that will, so far as we have been able to find out, differentiate this book from all other introductory texts. We have included in the eleventh edition a substantial discussion of the role of the entrepreneurs and of the microtheory of their activities, their pricing and their earnings, and the implications for economic growth. Several studies of the place of the entrepreneur in economics textbooks (including earlier editions of this one) have all reached the same conclusion: that entrepreneurs are either completely invisible or are virtually so. Indeed, in a substantial set of the textbooks the word entrepreneur does not even appear in the index.