This book is concerned with one of the most urgent problems of scientifically based planning and control of the development of science and technology - contemporary methods of analyzing and forecasting trends in scientific and technological progress. The materials for this book are the most recent developments of Soviet and foreign students of science and also on the research carried out by the scientific collective headed by the author. The book presents the original theoretical conception of scientific and technological forecasting and outlines forecasting methods of interest both for practical planning works in the field of scientific and technological development, and for the projection of complex scientific and technological objects required in advanced scientific information. Similarly, the work is one of the first books in the USSR which systematically outlines and analyzes the contemporary state of scientific and technical forecasting as a complex problem in the study of science. Since this problem is of interest for wide circles in the scientific and technological community, the book has been written in a form intended for general use.