From [Wikipedia](http://en.wikipedia.org/wiki/Finance):

> Finance is a field that deals with the allocation of assets and
> liabilities over time under conditions of certainty and uncertainty.
> Finance can also be defined as the science of money management. A key
> point in finance is the time value of money, which states that
> purchasing power of one unit of currency can vary over time. Finance
> aims to price assets based on their risk level and their expected rate
> of return. Finance can be broken into three different sub-categories:
> public finance, corporate finance and personal finance.