We will trace the historical path that the device has taken to measure time, from the dawn of mankind to the present day: from banal solar to the most modern - hydrogen. You will read the history of the clock, learn that the clock is alive, water, sand, fire, tower, pocket, sea, pendulum, skeletons... The reader will find stories about watches that have become legends: Big Ben and the Kremlin chimes, Prague's Orloy and Zwinger watches, Old Joe and Greenwich watches, the Jaffa clock tower and Zitglogg... You will find many interesting facts about the mechanism counting history on the pages of this book, you will learn that: the simplest devices for determining time appeared more than 4000 years ago; flowers open with such accuracy that they can be used to determine the time of day; the expression "time flows" - came from the water clock - clepsydra; the accuracy of the hydrogen clock is the highest, it is 0.45 nanoseconds in 12 hours; and many more interesting things.