Two Letters by N. N. Luzin to M. Ya. Vygodskiĭ

The two letters of Nikolal Nikolaievich Luzin (1883-1950) to Mark Yakovlevich Vygodskil (1883-1950) now being published are kept in Moscow's Central Municipal Archive (stock 2894, schedule 1, work 237). The letters are handwritten, in ink, the first on eight large cross-ruled sheets and the second on unruled sheets of standard size folded in two. There is also a copy of the first letter, probably typed by Vygodskil. At the top of both versions of the first letter there is a handwritten note, which reads: [1930-1931] From acad. N. N. Luzin. The note is most likely Vygodskil's. The first letter is Luzin's response after receiving from Vygodskil a copy of his newly published course of mathematical analysis [1]. On the cover is the date of publication-1931. The book's introduction is dated 14 May 1931. This suggests that Luzin's first letter was written late in 1931 or early in 1932. This is corroborated by its beginning ("I have known for a long time about its publication and have heard about the impassioned debates it has provoked.... A lot of time has passed since the book's appearance, and most people have managed to speak their-very different-minds... "). The second letter was dated 20.XII.1933 by Luzin himself. The person who familiarized herself with these archive letters before V. A. Volkov and myself, was N. S. Ermolaeva. Vygodski-'s book Foundations of Infinitesimal Calculus (there were three editions published in 1931, 1932, and 1933) was based on a course of lectures presented by him at the Moscow Chemico-Technological Institute. These lectures were a radically non-traditional account of the differential and integral calculus. Vygodskiexplained the essence of his approach as follows: