For geologist Zalasiewicz, each and every pebble you find in your garden or on a shoreline is a "capsule of stories" which tell the dramatic history of the Earth. From the "pebble menagerie", he chooses a piece of slate lying on a Welsh beach, then embarks on a fascinating journey into the "enormous atomic vault of the pebble". Surprisingly, half of its mass is oxygen bound up with minerals such as silicon and aluminium. Some of its atoms (such as iron) come from deep within the Earth's super-heated mantle; others (sodium, chlorine) from the oceans. A few of the more exotic atoms come from space, or are the product of our atomic age, such as plutonium. Zalasiewicz's geological narrative shifts from atoms to silt grains washed from the now vanished continent of Avalonia, then crushed at unimaginable pressures in the Earth's "tectonic vice". Moving through deep time, he takes the reader into the microscopic realm of minerals and microfossils before venturing into a far future in which the pebble's atoms are reabsorbed into a new star system.