History of Science and Engineering Annotation << Back Analysis of Notes from L. Euler's Notebooks, in Which the Questions of the Theory of the Beta Function Are Considered Ignatushina I.V. The great scientist Leonard Euler (1707–1783), one of the founders of modern mathematics, played a decisive role in the formation of some sections of the theory of special functions. In particular, he introduced the concepts of gamma (G) and beta(C) functions and obtained important results regarding the properties of these functions, which are widely used in various branches of modern science. The proposed article presents a detailed analysis of the notes from his notebooks devoted to the theory of the B-function. This material allows you to get acquainted with the scientifi c laboratory of the great scientist, to understand how important results of this theory were obtained, as well as to clarify the dating of their discoveries. Keywords: Beta function and its properties, history of special functions, L. Euler. DOI: 10.25791/intstg.3.2024.1469 Pp. 03-16.