This document discusses the concepts of law of demand and supply, movement and changes in demand and supply curves, and the relation between emerging theories in 21st century economies with those of the 20th century. It explores the factors affecting demand and supply, as well as the shifts in demand and supply curves. Additionally, it examines the contemporary economics and its relation to neoliberalism and the digital economy. The document also compares the changes in contemporary economics from the 20th century to the 21st century, and discusses the modern inequality theory of economics.