In the beginning of April, 1905, I received from Berlin a very unexpected invitation to deliver a popular scientific lecture at the Academy of Music in that city. I at first declined this flattering invitation, with thanks, sending them a copy of a printed declaration, dated 17th July, 1901, which I had made frequent use of, to the effect that "I could not deliver any more public lectures, on account of the state of my health, my advanced age, and the many labours that were still incumbent on me." I was persuaded to make one departure from this fixed resolution, firstly, by the pressing entreaties of many intimate friends at Berlin. They represented to me how important it was to give an account myself to the educated Berlin public of the chief evolutionary conclusions I had advocated for forty years. They pointed out emphatically that the increasing reaction in higher circles, the growing audacity of intolerant orthodoxy, the preponderance of Ultramontanism, and the dangers that this involved for freedom of thought in Germany, for the university and the school, made it imperative to take vigorous action. It happened that I had just been following the interesting efforts that the Church has lately made to enter into a peaceful compromise with its deadly enemy, Monistic science. It has decided to accept to a certain extent, and to accommodate to its creed (in a distorted and mutilated form) the doctrine of evolution, which it has vehemently opposed for thirty years. This remarkable change of front on the part of the Church militant seemed to me so interesting and important, and at the same time so misleading and mischievous, that I chose it as the subject of a popular lecture, and accepted the invitation to Berlin. After a few days, when I had written my discourse, I was advised from Berlin that the applications for admission were so numerous that the lecture must either be repeated or divided into two. I chose the latter course, as the material was very abundant. In compliance with an urgent request, I repeated the two lectures (17th and 18th April); and as demands for fresh lectures continued to reach me, I was persuaded to add a "farewell lecture" (on 19th April), in which I dealt with a number of important questions that had not been adequately treated.