My assignment is to trace the development of quantum electrodynamics. This topic is intended to be an example of the general theme of the symposium — the "Development of the Physicist's Conception of Nature". But, as Dirac pointed out, the phrase "the physicist's conception" implies a degree of unanimity that rarely exists during the period of active development of a subject. Only when the material is finally frozen in the textbooks can one speak of "the physicist's conception". At any interesting moment during the period of development there are discordant viewpoints of individual physicists. What is the present status of quantum electrodynamics, the modern version of which is now some twenty-five years of age? Perhaps I can emphasize that the development phase is not yet terminated by telling you that I have just finished writing a book — Particles, Sources, and Fields, Vol. II — in which the major quantitative accomplishments of modern quantum electrodynamics have been derived, not as they were done historically, but by a conceptually and computationally simpler method. It is through this method, source theory, that I believe future generations will learn quantum electrodynamics from their textbooks.