A. Church has contributed a lot to the safeguard of G. Frege's theory of meaning after the discovery of antinomies in it. To achieve this he has adapted it by keeping parts, discarding others and adding new ones, most of which are clearly exposed in an informal way in the introduction to his Introduction to Mathematical Logic. As for any modification of a theory by another person, it is interesting to understand how the thoughts of the former survive in the new theory even though radical changes have occurred, or on the contrary how it retains only the appearance of the initial theory. We shall therefore go through the basic concepts of logic he introduces in this introduction and assess their relation to Frege's original theory.