To build a solid house, one needs a solid foundation. In macroeconomics, this foundation centers on a few key questions: How do we measure overall economic activity? What are the relevant aggregates (totals) needed to measure overall economic activity? What role do governmental and other institutional policies play in an economy? What are some important components that affect the whole economy? Because macroeconomics concerns itself with so many different parts of the economy, it is critical to focus on these key questions and ideas before moving on to the parts themselves.