“Alexander Stepanovich,” Gorky said in the evening after dinner, when everything in the world had already been discussed and tea with raspberry jam had been drunk, “I know you are a person who questions any observation. Nevertheless, didn’t it seem to you that a dog was howling wildly in the house of Academician Ivan Petrovich Pavlov last night?” They didn't think so. You will howl here when... However, it is no coincidence that this story takes place on Good Friday. There is perhaps no better day to think about what it really means to do good. Thinking about science every minute? About service to the Fatherland? What if it's evil? How to deal with it? Explode, uproot, wipe off the face of the earth? What if you made a mistake and good and evil suddenly change places? Let these questions overcome theorists, but the famous physicist Alexander Stepanovich Popov is a practical man. He always knows what to do.