The pendulum is a constant source of interest to scientists. Great and well-known inventors such as Galileo, Huygens, and Kelvin all devised mechanisms to maintain its even oscillations. Others such as John Harrison, Lord Grimthorpe, and William Shortt are known only in horological circles but contributed as much or more over three centuries. By writing a personal account of his own inventions and achievements in horology the author involves the reader in the history of precision time-keeping before the advent of atomic clocks and the quartz chip. Escapements, the mechanisms that drive pendulums, are a delight to the geometrical mind as well as a delicate and subtle challenge to the mechanical engineer. In their most refined form pendulum clocks not only keep astonishingly accurate time they are also sensitive enough to detect the ebb and flow of tides and even the ceaseless quivering of the Earth itself. Philip Woodward's deep knowledge of and passion for time-keeping mechanisms is evident throughout this highly readable and fascinating account of precision horology.