This report covers the importance of understanding consumer behaviour for a business entity, with a focus on the example of Marks and Spencer. It includes an analysis of the stages of the consumer decision-making journey, how to understand customer needs, the black box model of decision-making, and the implications of marketing mix and model. The report also compares and contrasts the key differences of the decision-making process in the context of B2C and B2B, and evaluates different approaches to market research.