In 1931, Lionel Robbins famously wrote "Economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses". This drew a line of demarcation between mainstream economics and other disciplines and schools studying the economy.
Economics has been initially shaped as a discipline concerned with a range of issues revolving around money and wealth. However, in the 1930s, mainstream economics began to mutate into a science of human decision.