Today, technology is an integral part of our lives. TV, computer, microwave, bus, subway, printer, player... In addition, everyone has been using mobile phones and tablets for a long time. Do you know how and why all these devices, machines and mechanisms work? What, for example, hides under the armor of a tank, and what is called the heart of a car, how the camera is able to capture one moment and capture it forever, why the helicopter is able to hang in the air and why the ocean liner does not sink, how the solar battery works and how the wind engine works, why the iron heats up, and the refrigerator freezes food - our encyclopedia will give answers to all these and many other questions.