When the decision to publish this new edition of the first two volumes of the Cambridge Ancient History was taken, it was apparent that it would not be possible to revise the former edition and that the volumes must be entirely re-written. The new volumes, which are about twice as long as their predecessors, are divided into two parts in order to key in with the numbering of the later volumes. This substantial increase in size is to be ascribed mainly to fresh knowledge which has been acquired during the past forty-five years as a result of more and more intensive efforts to discover the past. Perhaps the most notable advances have been made in our knowledge of the very early phases of man’s existence in settled communities: excavations at Catal Hiiyiik in Anatolia have disclosed a city, dated to the seventh millennium B.C., which extends at least over an area of thirty-two acres, while smaller towns or villages of approximately the same date have been found in the Jordan valley at Jericho, in Iraq at Jarmo, in the foothills of Kurdistan, on the north Syrian coast at Ras Shamra, in Cyprus at Khirokitia and at Argissa in Thessaly. Settled communities presuppose the domestication of animals and the cultivation of crops, landmarks in social evolution which are now believed to have been reached between the tenth and the eighth millennia B.C. Behind these achievements lay perhaps more than 40,000 years of human development, if the dates obtained by carbon-14 determination for the Palaeolithic Age are reliable. This invaluable aid to the archaeologist, which we owe to the American scientist Professor W. F. Libby, is still lacking in precision, but improvements in technique and in the interpretation of results can hardly fail to come in time. However remote from the present day such dates as have been obtained by this method for the Palaeolithic Age may seem they are recent in comparison with the earliest evidence of primitive life in Cambrian rocks, which are believed to be 600 million years old and thus to date from nearly 4,000 million years after the earth came into existence.

Chronology, the subject of chapter vi in this volume, has always presented difficult problems to the ancient historian, and it must be admitted that complete agreement has not yet been achieved, in particular for the third millennium B.C.