The conception of the reading as a “communication echo” (feedback) allows being derived a formula of Energy conversion efficiency (ECE) of the book. The conclusion is that a book of high efficiency is the one that systematically provokes feedback and the one that is in the continuous dynamics of a spiral communication cycle and cascade reactions from readers. An applied contribution of the study is the algorithm for studying of the reader's feedback with a book. The algorithm is applicable both to the ecosystem of the book and other content industries as well as to the purposes of the political communications. The conclusion of the research is that in the resonance field (the field of reading as feedback) is passing an inversion process: the reader becomes from recipient an initiator who generates new spaces for full of matter and market use of the book (in the field of education, the tourism, the advertising, the goods and services industry etc.) and continues the process of revalorization of the book as a basic cultural media. Practical implications: Useful and interesting for scientific researchers, publishers, booksellers, and librarians.

Keywords:reading as communication, sociology of reading, feedback monitoring, medialogic approach, resonant model of communication, spiral model of communication, model of the pyramid, Matryoshka model, book as medium, impact of the book, reach of books, Energy conversion efficiency, publishing workflow, content industry, media and cultural industries