In 1900, Queen Victoria still ruled over the British Empire, the imperial Manchu dynasty over China, and the Romanov Tsars over Russia. The cinema was in its infancy, with radio and television still to be developed. The earliest cars were on the road, but air travel was yet to come. Before antibiotics and effective vaccines against many common diseases, death rates were high. Over the course of the twentieth century, the human population of the world has tripled, space travel has left the realms of science fiction and become reality, two cataclysmic world wars and a host of other conflicts have been fought, the internal combustion engine has replaced the horse as the basic means of transport, computer technology has revolutionized communications. In this book, some of the most distinguished historians in the world survey the momentous events and the significant themes of recent and contemporary times, with a look forward to what the future might bring. They trace the continuities which have persisted over a hundred years and analyse the changes which have marked the century's progress.