When making mistakes or encountering strangers, we calm ourselves with the phrases "It is human to make mistakes." But do they comfort someone who has fallen victim to someone else's incompetence? And do they comfort the doctor who couldn't help? We want to believe that the doctor is infallible in his workplace. In the operating room, he is omnipotent, never gets tired or feels bad, does not get annoyed or distracted by extraneous thoughts. But what does it really feel like to be a neurosurgeon? What is it like to know that not only the patient's life depends on your actions, but also his personality - the ability to think and create, to be sad and rejoice? Sooner or later, every neurosurgeon inevitably asks these questions, because any operation is associated with great risk. Henry Marsh, the world-famous British neurosurgeon, pondered them throughout his career, and the result of his reflections was an exciting, extremely frank and poignant book, the main idea of ​ ​ which can be put into two short words: "Do no harm."