Abstract:  
The article presents a theoretical research of the terms 'idiolect' and individual style or 'idiostyle'. The author fo the article outlines the problems in the sphere of studying the phenomenon of idiostyle and idiolect that need to be solved such as differentiatio between conventional and individual, the use of idiostyle outside creative writing, quantitative features of idiostyle, etc. The author offers a classification of idiostyle aspects such as cultural historical, genre, psycholinguistic, cognitive, axiological, systems structural, linguopoetical, semantic stylistical, etc. The author demonstreates that the communicative-stylistic (pragmatic) parameter is the most important for creating an individual style. To create the idiostyle model, the researcher defines the writer's intentions in the texts under study. The main instrument for the differentiation between terms is the terminological line 'linguistic personality - speech personality - communication personality'. The image of the writer is the result of his or her use of the idiostyle as part of text and intra-textual relations. The practical realisation of the communicative stylistic aspect is demonstrated based on the analysis of a creative legacy of a journalist, publisher and Russian educator of the XVIIIth century N. I. Novikov. The idiostyle is viewed as the key characteristic of the authorship and a result of targeted writing activity.