This book is an attempt to tell about what I knew centuries ago, but a competent, scientific explanation for which was found relatively recently: the discovery of the thermal conductivity of semiconductor elements - crystals (the second Nobel Prize in physics, received by Zhores Alferov), allowed medicine to step far forward. But it just so happens that one of our science is still going leaps and bounds forward, and the second, crushed by functionaries, is marking time.