TO THE FIRST RUSSIAN EDITION It was a very difficult task to write a guide-book of a small size designed to contain the fundamental knowledge of mathema­ tics which is most necessary to engineers and students of higher technical schools. In our tendency to the compactness and brevity of the exposition, we attempted, however, to produce a guide-book which would be easy to understand, convenient to use and as accurate as possible (as much as it is required in engineering). It should be pointed out that this book is neither a handbook nor a compendium, but a guide-book. Therefore it is not written as systematically as a handbook should be written. Hence the reader should not be surprised to find, for example, I'HOpital's rule in the section devoted to computation of limits which is a part of the chapter "Introduction to the analysis" placed before the concept of the derivative, or information about the Gamma function in the chapter "Algebra"-just after the concept of the factorial. Thereare many such "imperfections" in the book. Thus a reader who wants to acquire certain information is advised to use not only the table of contents but also the alpha­ betical index inserted at the end of the book. If a problem mentioned in the text is explained in detail in another place of the book, then the corresponding page is indicated in a footnote.