Preface; 1 Time: pre-twentieth century; 2 Solar time; 3 Ephemerides; 4 Variable Earth rotation; 5 Earth orientation; 6 Ephemeris time; 7 Relativity and time; 8 Time and cosmology; 9 Dynamical and coordinate time scales; 10 Clock developments; 11 Microwave atomic clocks; 12 Optical atomic standards; 13 Definition and role of a second; 14 International Atomic Time (TAI); 15 Coordinated Universal Time (UTC); 16 Time in the solar system; 17 Time and frequency transfer; 18 Modern Earth orientation; 19 International activities; 20 Time applications; 21 Future of time keeping; Acronyms; Glossary

This accessible reference presents the evolution of concepts of time and methods of time keeping, for historians, scientists, engineers, and educators