Individual income can grow only as fast as productivity rises.

As they grow, companies saturate their markets, become more complex and difficult to manage, and face larger and more entrenched competitors.

Expenditure rises to meet income.

Higher productivity enables companies to increase sales without adding workers. Even if job markets tighten and wages rise, corporate profits can continue to climb as long as worker productivity is growing faster than overall wages.

If only the human body could handle trauma as well as biotechnology stocks do.

Macroeconomics is the analysis of the economy as a whole, an examination of overall supply and demand. At the broadest level, macroeconomists want to understand why some countries grow faster than others and which government policies can help growth.