A two-volume book of scientifi c works by Leonid L. Kasatkin was published. The publication includes works written in the XXI century. Most of them were published earlier, some are published for the fi rst time. The need for reprinting works is that they are often printed in publications that are not always available not only to fans of the Russian language, but also to specialists. Leonid L. Kasatkin is a whole epoch in modern Russian stu dies. Starting as a talented and thoughtful dialectologist, Leonid L. Kasatkin expanded his scientifi c interests, and gradually became the leading phonetician in Russia. His works on phonetics, phonology, orthoepy, dialectology inherited the best traditions of the Moscow linguistic school and entered the golden fund of modern Russian science. The two-volume book includes the following sections: VOLUME I: I. Phonetics. II. Orthoepy. III. Phonology. IV. Spelling. V. Phonetists; VOLUME II: I. General problems of dialectology. II. Description of dialects and individual dialect features. III. Description of Russian dialects by village tales. IV. The stories of the villagers. V. History of the Russian language. VI. Dialectologists.