Very often, when visiting a doctor, we are faced with misunderstanding and even, as it seems to us, indifference. But most of us want to meaningfully participate in our own examination and treatment, to understand not only the fact that there is a deviation from the norm, but also what it means. Each of us wants to be confident in the correctness of the prescribed treatment, to understand what medications are prescribed to us and why, and not blindly follow the doctor’s recommendations. The book you are holding in your hands is not an ordinary guide to deciphering tests. This is your personal guide that will answer all your questions, help you navigate critical situations, teach you how to understand tests, and also tell you how to properly conduct a dialogue with your doctor. Reissue of the book “Tests and Diagnoses. How can we understand this?