Alfred Marshall was a prominent British economist, born in 1842 and known for his influential work in the field of economics. He is best recognized for his book, Principles of Economics, published in 1890, which helped establish the foundations of microeconomic theory. Marshall introduced key concepts such as elasticity of demand and the idea of consumer surplus, which are still widely used today. Marshall also played a significant role in the development of the Cambridge School of Economics, where he taught and mentored many future economists. His work emphasized the importance of both theoretical and practical aspects of economics, bridging the gap between the two and influencing economic thought for generations.