The economic history of the late Middle Ages is substantially better documented than that of earlier ages, thanks to thirteenth-century improvements in administration and commercial organization, and to the growth in urban literacy and numeracy. It is also substantially more complex, in that it includes no fewer than three distinct sub-periods: the tail of a secular wave of demographic and urban growth, economic expansion, and growing international trade associated with the late twelfth and thirteenth-century ‘commercial revolution’, that came to an end in the early 1300s; a century or more of demographic, economic, and social ‘crisis’, ‘involution’, ‘depression’, and ‘structural change’ ending in the mid- to late 1400s; and the first stages of a new, more dynamic, market-oriented, early capitalist upswing that lasted to the early 1600s. Consequently, interpretations of such a complex era have been intensely controversial. The chapter deals with the discussion and revision of the main issues related to such complexity.