The Time Book

Subtitled ‘A brief history of time, from lunar calendars to atomic clocks’, this quirkily illustrated guide explores questions such as what is time, how is it measured and how do we know it is accurate. The author explains how animals have inbuilt clocks, knowing when to hibernate, migrate, or in the case of honey bees the ability to time flights to gauge speed and distance from the hive. Humans too are ruled by these circadian rhythms, but our ancestors only put effort into developing calendars once there was a need to record and predict time. Interestingly almost everywhere calendars and religion are closely linked. The book traces the development of recording devices from lunar calendars of the Ancient World to the Julian calendar adopted by the Romans, which was only replaced by the Gregorian calendar in the 16th century. The book also describes the development of clocks from Ancient Egyptian sun clocks and Babylonian water clocks to the accurate watch developed by John Harrison that enabled sailors to establish longitude. The quest for accurate timekeeping was driven by the arrival of railways and the need for timetables. The conclusion is that in spite of the accuracy of today’s atomic clocks, Einstein has made us question whether we really understand time. A thought-provoking book that spans history, science and philosophy in an accessible way.