This document discusses demand, factors that affect demand, and key concepts related to demand curves. It defines demand and explains that demand depends on willingness and ability to pay. Factors that can cause demand to shift include income, price of substitutes or complements, population, and consumer tastes. The law of demand is explained as quantity demanded decreasing as price increases, ceteris paribus. Exceptions to the law and movements along versus shifts of the demand curve are also summarized. Types of demand like price and income demand are defined. The importance of demand analysis for business is highlighted.