James Chen, CMT is an expert trader, investment adviser, and global market strategist. Thomas J. Brock is a CFA and CPA with more than 20 years of experience in various areas including investing, ...

It is one of the basic principles taught to students studying economics. Introduced by Lord Alfred Marshall, it forms a crux in the micro-economic level often reflected in routine, day-to-day life.

Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Michael Boyle is an experienced financial ...