What is logic? What does this ancient and at the same time always young science do? Why is it needed, is it possible to do without it, and what role does it play in a person’s life? What are forms of thinking and what are the basic laws of thinking? What do the numerous logical errors that we involuntarily or consciously make in thinking and speech lead to? What is evidence and what are its types? What are the basic rules of evidence and the errors that arise when they are violated? How to make your thoughts clear and distinct, how to express them so that others always understand what you want to say; How to defend your point of view and convince your interlocutor? How to competently conduct a discussion and win an argument? What are sophisms and logical paradoxes? You will learn about all this by reading the book, which differs from many other textbooks on logic in that it will not be difficult to read: the author, who has been teaching logic to students and schoolchildren for many years, has tried to make the material presented to your attention simple and clear, and, if possible, interesting and fascinating. The book is addressed to students and schoolchildren studying logic, teachers - as an exchange of teaching experience - and everyone interested in logic and other humanities.