The article analyzes the construction of a mirror universe in the structure of the art world in the novel “The Handwriting of Leonardo” by D. Rubina. The mirror here acts as a universal world substance, a vital substance, manifesting itself in a variety of forms and determining the storyline and the fate of the characters. This thesis statement has determined the aim of the article – to identify, systematize and define the roles and functions of the mirror in the novel; the focus is not on the spatial and temporal level of the text, but on the level of character and image. At the initial stage of the research, following Y. Levin, we conceptualized the data of our lexical-statistical analysis, identifying “semiotic potencies of the mirror” in the novel: the mirror as a space-forming element, the mirror as a key-cipher to Anna Nesterenko’s inner world, the mirror as a central detail-symbol of the novel. The next step was to create a coherent conceptual description of the mirror continuum in D. Rubina’s novel. As a result of the research, we have come to the conclusion that the construction of the novel’s mirror universe and the new role-functions by the mirror substance takes place step-by-step. The mirror in D. Rubina’s “The Handwriting of Leonardo” is not just a stable motif, but one of the semantic and symbolic principles that are reflected in the emblematic structure of the work. This is the basis on which the author constructs the configuration of her world.