The collection includes the final works of the great Russian encyclopedic scientist D. I. Mendeleev on demographic and economic issues. For the first time in post-revolutionary years, the book "To the Knowledge of Russia" is published without cuts according to the publication of A. S. Suvorin in 1907. It analyzes the results of the First General Census of the Russian Empire (1897) and gives a forecast of population growth until 2000. Specialists and simply inquisitive readers will give rich food for comparison and reflection.