For decades, this book served as the main textbook on logic and the scientific method in most American universities and is still in demand (the last reprint in English was published in 2007). The authors managed to organically combine Aristotle's syllogistics with the formalized language of mathematical logic, and they present the methodology of knowledge in close connection with logic. All standard topics taught in the basic logic course are covered, and their presentation is more detailed than in standard textbooks. As a synthetic course in logic and scientific methodology, it has no analogue among domestic textbooks. A significant part of the book is devoted to the study of problems of applied logic: experimental research, induction, statistical methods, analysis of value judgments. The book provides an analysis of the subject of logic and the nature of the scientific method, consideration of the role which methods of logic play in scientific knowledge, as well as criticism of many alternative approaches to the interpretation of logic and science in general. In this regard, it represents an independent philosophical work and will be of interest to specialists in the field of philosophy and methodology of science. For teachers of logic, philosophy of science, theory of argumentation and concepts of modern natural science, students studying logic and methodology of science.