"The Lonely Crowd" is a sociological book written by David Riesman in 1950. It explores the shift in American society from traditional, inner-directed individuals to other-directed individuals who are influenced by social expectations and peer pressure. Riesman argues that this change leads to a sense of isolation and loneliness, despite being surrounded by others. The book categorizes people into three types: inner-directed, other-directed, and tradition-directed. Inner-directed individuals rely on their own values and beliefs, while other-directed individuals seek approval from their peers. Tradition-directed individuals adhere to established norms and customs. Riesman's analysis highlights the complexities of modern social life and the impact of conformity on personal identity.