These volumes contain key texts from the period 1860-1939, covering a long list of Anglo-Saxon writers, as well as the most important contributions from the French, German, Italian, Russian and Swedish debates. The older business cycle theories presented here richly elucidate the complex interaction between and real, monetary and structural change factors in economic systems -- the close association between historical and analytical methods providing a fertile source of inspiration for current researchers in the field. This first part covers early classics, structural theories, monetary theories of business cycles, and the relation between equilibrium and the business cycle.