The idea of ​ ​ publishing a collection of unresolved problems of group theory was expressed by Mikhail Ivanovich Kargapolov (1928-1976) at the Day of Problems of the First All-Union Symposium on Group Theory in Kourovka near Sverdlovsk on February 16, 1965. Therefore, this collection was called "Kourovskaya notebook." Since then, every 2-4 years, another publication has appeared, supplemented by new questions and brief comments on solved problems from previous editions. The "Level Notebook" has been a kind of communication tool for specialists in group theory and related areas of mathematics for more than 50 years. Perhaps the most striking example of the success of the "Kourovskaya Notebook" is the fact that about 34 of all problems from its first edition have already been solved by now. Having gained international recognition, "Kourovskaya notebook" has over 300 problem authors from many countries of the world. Starting from the 12th edition, the Kourovskaya Notebook is published in parallel in Russian and English. In the section "Archive of solved problems" all tasks are placed, the commentary on which in one of the previous editions indicates a detailed publication containing a complete answer. However, those problems whose full references to solutions first appear only in this edition are commented on in the main part of the Kourovsky Notebook, among the unresolved problems of the corresponding paragraph.