The Measurement of Time: Time, Frequency and the Atomic Clock 1st Edition

It's very good.

One of the best books in this area. Beautifully written. Thorough and comprehensive, with an emphasis on the principles. F. G. Major's book the Quantum Beat is a great book too. Best to have both of them.

I found this excellent translation from the original French to be a most authoritative and lucid treatment of the physics and metrology of time on a superior technical level, by two of the most prominent figures in the field. It gives comprehensive coverage of atomic frequency standards including the most recent advances involving cold atoms and trapped ions, such as the the cesium "fountain" and mercury ion standards. I consider this book essential reading for anyone with an ambition to become steeped in the field, and offers a more technically sophisticated treatment than is attempted, for example, in a book such as "Quantum Beat".