The “Letters to a German Princess on Various Physical and Philosophical Matters” offered to the reader occupy a special place in the scientific heritage of Leonhard Euler. The work is written in an epistolary form, unusual for Euler, and is a statement of the foundations of natural science and philosophy of that time in his interpretation; it bears a vivid imprint of the author’s personality, his many years of searching and thinking about the nature of physical phenomena, his ideas about the structure of the Universe, and the philosophical and physical picture of the world. This very serious and complex scientific material is presented in the form of letters-conversations, in which scientific rigor is combined with clarity and accessibility of presentation, designed for an unprepared reader. The “Letters” were published anonymously, but Euler’s authorship was no secret to anyone. For the first time, “Letters” were published in St. Petersburg in French and in Russian translation.

CONTENTS: Volume one (7). Volume two (171). Volume three (343). APPENDICES: L. Euler. Letters to the German princess about various physical and philosophical matters (From the editor) (533). Yu.X. Kopelevich, N.I. Nevskaya, E.P. Ozhigova. The history of the creation of “Letters to the German Princess” and their addressees (535). N.I. Nevskaya. St. Petersburg sources of Euler's physical and philosophical views (555). E.P. Ozhigova. Editions of “Letters to the German Princess” and their evaluation (610). Ya.A. Smorodinsky. “Letters to a German Princess” by L. Euler and 18th century science (617). Comments (N.I. Nevskaya) (636). List of illustrations (711).