At the beginning of the 20th century, a single community of critics of children’s literature began to form, who called for a more responsible and thoughtful choice of books for children’s reading. The article presents Olga Kapitsa’s point of view on the principles of compiling indexes of children’s literature. Based on archival materials from the Children’s Reading Demonstration Library, an overview of the discussion on the first part of the “Systematic Index of Books for Children and Youth” devoted to fairy tales is given, and the principles of evaluating the works of various authors are also revealed: writers who write specifically for children, Russian and foreign classics. According to Olga Kapitsa, first of all, in works for children, it is necessary to pay attention to such subjective and evaluative signs as a comfortable narrative atmosphere for the child reader, the ability to arouse his interest, the absence of false intonations and excessive sentimentality or deliberate bias in the author’s “appeal” to children, at the same time texts they should be artistic and written in figurative language, and the publications should be qualitatively decorated and illustrated. The formulation of the criteria and the arguments for their allocation in the works by Olga Kapitsa demonstrate not only the conceptual apparatus of the pedagogical discourse on children’s reading in the 1910–the 1920s, which had been formed at the previous stage of the development of children’s literature criticism but also the influence of the new bibliographic approach to the description of the book flow for children during this period.