The author has set himself the task of dealing in this article with the question of the importance of textbooks for working people who study. By analysing the pedagogical process, especially that of university extension courses, he tries to show that the textbook, as one of the basic pedagogicodidactical means, fulfils a specific function in this process, resulting from the characters of this process. In many cases the textbook has to replace the direct work of the teacher, his spoken word, as well as the whole process of studies consisting in a firm system of seminars, practical exercises, and quided practice of the regular study. Even though the aim and content of the extension and the regular courses are the same, and thereby requirements as regards standards arc also the same, the character of the pedagogical process óf an extension course is different from that of a regular course, and therefore the function of the textbook in this process is also different. This necessarily results in special requirements as to writing textbooks for extension and correspondence courses, 'vhich are one of the forms of study provided for the working people during employment. A textbook for extension courses ought to combine in itself both the instructional, technically scientific aspect and the methodical aspect. Only in this way could it help effectively to develop the pedagogical process of the extension or correspondence course and especially lead to an independent study of the working people. A wrong approach to the function of textbooks in the pedagogical process of an extension and correspondence course might lead to transferring mechanically the means and methods of regular courses to extension and correspondence courses, thereby making the courses of study for working people more difficult, and, eventually, lowering the standards of these forms of study.