About eighty million people today can trace their descent back to the occupants of Ireland. But where did the occupants of the island themselves come from and what do we even mean by "Irish" in the first place?

This is the first major attempt to deal with the core issues of how the Irish came into being. J. P. Mallory emphasizes that the Irish did not have a single origin, but are a product of multiple influences that can only be tracked by employing the disciplines of archaeology, genetics, geology, linguistics, and mythology.

Beginning with the collision that fused the two...