Economic Activity has its origins in a course of lectures given since 1950 to first-year undergraduates at the University of Adelaide. That course was originally given by P. H. Karmel; in later years the other two co-authors inherited it. Little attention was paid to financial factors in the first-year course. A second-year course of macro?economics (given on several occasions by R. H. Wallace) was built upon the first course, and in this the inter-relationships...