This chapter introduces the key themes underpinning the development of archaeological theory over the last 50 years. These five decades have been ones of theoretical and philosophical ferment in just about every aspect of archaeology. During those years the relationships between archaeology and the societies that sustain it have also changed, bringing additional sources of pressure to fundamentally transform the discipline itself. Archaeology has come to exhibit such significant diversity it is reasonable to question whether the history of these last decades has been a history of rising disciplinary incoherence. Archaeology is now very much more than the business of archaeologists.