This book is a collection of scholarly studies in the history of mathematics education, very abbreviated versions of which were presented at the ICMI Congress in 2021. The book discusses issues in education in Brazil and Belgium, in Poland and Spain, in Russia and the United States. Probably the main factor that unifies the chapters of the book is their attention to key moments in the formation of the field of mathematics education. Topics discussed in the book include the formation and development of mathematics education for women; the role of the research mathematician in the formation of standards for writing textbooks; the formation of curricula and the most active figures in this formation during the New Math period; the formation of certain distinctive features of curricula in Poland; the formation of the views of David Eugene Smith and the influence of European mathematics education on him; the formation of the American mathematics community; and the creation of such forms of student assessment as entrance exams to higher educational institutions. The book is of interest not only to historians of mathematics education, but also to wide segments of specialists in other areas of mathematics education.