The human relations theory introduced sociology and psychology to administration, and these new assumptions were crucial to the understanding and interaction of the new vision of the worker within the organization. Understanding people is an extremely relevant factor for all professionals, regardless of their line of work, because organizations are formed by individuals who develop relationships. Book recommended for professionals in the management area, application in undergraduate and graduate management courses. An important work for professors in the research of knowledge about organizational behavior, class preparation, bibliography of subjects that involve the theme, textbook for students to develop critical and reflective capacity about human behavior in organizations, and practical applications.