Frank Mitchell and a group of fellow-naturalists hop aboard a magic carpet which whisks them back in time, some 1700 million years, on a mammoth geological tour of Ireland. Professor Mitchell provides an eye-witness account of the major changes occurring over the million years of their journey, which begins 6km north-west of the Inishowen coast in Donegal, on the tiny island of Inishtrahull, site of the oldest rock so far recognised in Ireland. The travellers witness mountain peaks forming, primitive land-plants appearing and new life-forms developing in the oceans, as the constantly changing climate and erosion shape and reshape the landscape. They are present for the birth of the modern Atlantic Ocean; they stand aside as volcanoes erupt to form the Giant's Causeway in Antrim. They experience the cold of the Ice Age, and the reappearance of woodland as the ice retreats. They are there to welcome the first human inhabitants, the Mesolithic hunter-gatherers, and their descendants, the first farmers.They witness the physical changes introduced by developments in the Bronze Age, the Iron Age and the medieval period, before arriving back in modern times and ending their journey on the banks of the Shannon. In Where Has Ireland Come From? Frank Mitchell has succeeded in giving us a succinct overview of the origins and development of the island of Ireland, from some 1700 million years ago to the present day.