Covering the "early historic" part of Scottish history, ca AD 400-1000, this book deals primarily with the emergence of the Pictish kingdom and its eventual merger with Dal Riata to become the kingdom of Alba, later known as Scotland. Other bits of what became Scotland, such as Lothian, are dealt with more peripherally. Foster subscribes to the view that the Pictish kingdom was created by the kings of Fortriu - i.e. the region around the Moray Firth - conquering the rest of eastern and northern Scotland, and that the union of Dal Riata and Pictavia was due to the same warlord, Kenneth MacAlpin, making himself king of both, rather than either simply conquering the other, or manipulation of a supposed matrilineal inheritance of the Pictish kingship (the actual usual method of chosing a new Pictish king being civil war). She rejects any notion that the Picts were particularly enigmatic or "different"; while they had their quirks, notably in their artistic traditions, they were basically one Dark Age "barbarian" people among many others in northwestern Europe.

The book is good on some things, such as ecclesiastical and art history, weaker on others, such as military history.