Just as I was completing this preface I received the publishers' notice of a new important book by Herr Duehring. "New Foundations for rational Physics and Chemistry." Although I am very well aware of my deficiencies in physics and chemistry I still believe that I know my Duehring well enough, without having read the book, to venture to say that the laws of physics and chemistry there set forth are worthy of being placed alongside of Herr Duehring's former discoveries and the laws of economics, scheme of the universe, etc., examined in my writings and proved to be misunderstood or commonplace, and that the rhigometer, an instrument constructed by Herr Duehring for measuring temperature will be found to serve not only as a measure for high or low temperature but of the ignorance and arrogance of Herr Duehring. _London, 11 June, 1878._ II It came to me as quite a surprise that a new edition of this work was called for. The special views which it criticised are practically forgotten to-day. The work itself has not only been placed before many thousands of readers by its serial publication in "Vorwaerts" of Leipsic in 1877 and 1878, but it has also been published in large editions in its entirety. How then can there be any further interest in what I have to say about Herr Duehring? In the first place, I fancy, that it is owing to the fact that this book, as indeed, all my writings at that time, was prohibited in Germany soon after the publication of the anti-Socialist laws. Whosoever was not fettered by the inherited officialdom of the countries of the Holy Alliance should have clearly seen the effect of this measure--the double and treble sale of the prohibited books, and the advertisement of the impotence of the gentlemen in Berlin, who issued injunctions and could not make them effective. Indeed the amiability of the Government was the cause of the publication of several new editions of my shorter writings, as I am able to affirm. I have no time for a proper revision of the text and so allow it to go to press, just as it is.