As a preliminary to any archaeological study it is necessary to consider two parameters: the spacial context within which societies under consideration developed and the time span covered. In the context of this book, space is restricted to the islands of Britain, excluding Ireland: the time span begins in the eighth century Be and ends in the first century AD. In the seven chapters to follow (chapters 3-10) various aspects of these themes will be discussed. Here, by way of introduction, we will consider the two parameters in the broadest of terms.