"Einstein's Clocks" is a dramatic account of the quest to synchronize time that culminated in Einstein's revolutionary theory of relativity. As Peter Galison argues, relativity was borne of urgent practical necessity. Clocks and trains, telegraphs and colonial conquest: the challenges of the late nineteenth century provided an indispensable real-world background to the theoretical breakthrough. One challenge that engaged the young Albert Einstein was that faced by Europe's burgeoning rail network. Only a century ago, the continent had hundreds of time zones, and no universal system for synchronizing them. Given that local time could vary from town to town, scheduling rail services was hard - but vital, not least to stop trains from colliding as they hurtled in opposite directions along single tracks. In his role as president of the French Bureau of Longitude - a remit of which was to map colonial Africa - Henri Poincare grappled with a similar issue. Synchronized clocks, set by telegraph signal from Paris, were necessary to determine longitude and provide the precise coordinates his cartographers needed. For "Einstein's Clocks", Peter Galison has culled unexplored archives and unearthed forgotten patents to tell the gripping story of these two giants - whose concrete preoccupations engaged them in a silent race towards a theory that overturned 200 years' received thinking.