Functional stylistics finds its origin in the works of Czech and Russian scholars of the 20-30s of the last century. In spite of great discoveries in its methodology, until the 1960s the functional-stylistic theory as an integrated and conceptual system has not been created. M.N. Kozhina's theory has had a great impact on the formation and verification of the functional-stylistic theory, her works on the theory of speech and the linguistic stylistics of the second half of the 60s and the beginning of the 70s of the 20th century were the first to reveal traces of development of linguistics from the systemic-structural to the functional-communicative paradigm. They were one of the earliest conceptions of the discourse analysis. Within this period M.N. Kozhina defined the main concepts and methods of functional stylistics, including the concept of functional style of speech, defined on the basis of extralinguistic factors. She regarded peculiarities of the main speech styles, as a result of realization of language peculiarities, typical for each communicative sphere, and the formation of stylistic-speech system. She created the classification of extralinguistic factors and the following classification of functional styles and their less varieties within the framework of functional theory. M.N.Kozhina founded the necessity of the interscientific research of styles and suggested definite patterns of their objective and stylistic-statistical analysis. These theoretical assumptions were later applied into the historical and comparative stylistics. In the 80-90s of the 20th century M.N.Kozhina considerably developed her theory. It resulted in the creation of one of the most interesting and influential trends, i.e. the functional stylistics of text. The subject of the research became a stylistic organization of the whole text as the representative of a text type, regarded within the integrity of its speech external and sense aspects, as well as of a wide cognitive, communicative and social context. She worked out the conception of special text categories, called functional and semantic-stylistic, and put out new ideas concerning cognitive and communicative factors, as form structuring components of the semantic structure of the text. The recent works of M.N. Kozhina deal with general questions of functional stylistics and with the working out of the foundations of the theory of speech as an integrated theory.