Economics is usually divided into two main branches:

Microeconomics, which deals with the behavior and interaction of individual agents and firms.
Macroeconomics, which examines an economy as a whole with a view to understanding the interaction between economic aggregates such as income, employment and inflation.
Attempts to join these two branches or to refute the distinction between them have been important motivators in much of recent economic thought, especially in the late 1970s and early 1980s. Today, the consensus view is arguably that good macroeconomics has solid microeconomic foundations i.e. its premises have support in microeconomics.

Within these major divisions there are specialized areas of study that try to answer questions on a broad spectrum of human economic activity (see below). There are also methodologies used by economists whose underlying theories are important. The most significant example may be econometrics, which applies statistical techniques to the study of economic data.

There has been an increasing trend for ideas and methods from economics to be applied in wider contexts. Since economics analysis focuses on decision making, it can be applied (with varying degrees of success) to any field where people are faced with alternatives - education, marriage, health, public policy, voting theory etc. Public Choice Theory studies how economic analysis can apply to those fields traditionally considered outside of economics. The areas of investigation in Economics therefore overlap with other social sciences, including political science and sociology.