Bernard M. Bass's 20-year research on transformational and transactional leadership highlights the importance of aligning organizational and individual interests. Transformational leaders inspire, intellectually stimulate, and consider individuals, while transactional leaders focus on immediate self-interests through contingent reinforcement. Transformational leadership is more effective in various settings, though its effectiveness can be influenced by context. Women leaders tend to be more transformational than men. A six-factor model of transformational/transactional leadership fits diverse samples, but fewer factors may be necessary. Transformational leadership is crucial for job satisfaction and organizational citizenship behavior, especially in today's dynamic work environment. Transformational leadership involves idealized influence, intellectual stimulation, and individualized consideration. It enhances follower maturity, ideals, and concern for others, the organization, and society. Transactional leadership, while effective, may not provide sufficient job satisfaction. The full range of leadership, as measured by the Multifactor Leadership Questionnaire (MLQ), includes both transactional and transformational factors, with leaders varying in their emphasis. Transformational leadership is essential in collectivist cultures, where leaders can more easily inspire and influence followers. It is also important in diverse settings, where leaders must navigate different ethnic, racial, and gender dynamics. Research indicates that women may be more transformational than men, though this needs further study. Training and development programs can enhance transformational leadership, with a focus on individualized consideration and intellectual stimulation. Measuring transformational and transactional leadership presents challenges, including multicollinearity and the need for reliable scales. The MLQ is a key tool, though its factors may vary across cultures. Transformational leadership is linked to follower self-concept, self-esteem, and collective efficacy. Future research should explore how context affects leadership effectiveness and how followers are transformed from self-interest to group or societal concern. New methods are needed to better understand the cause-effect relationships in leadership. Overall, transformational leadership remains a vital area of study for effective organizational and societal development.Bernard M. Bass's 20-year research on transformational and transactional leadership highlights the importance of aligning organizational and individual interests. Transformational leaders inspire, intellectually stimulate, and consider individuals, while transactional leaders focus on immediate self-interests through contingent reinforcement. Transformational leadership is more effective in various settings, though its effectiveness can be influenced by context. Women leaders tend to be more transformational than men. A six-factor model of transformational/transactional leadership fits diverse samples, but fewer factors may be necessary. Transformational leadership is crucial for job satisfaction and organizational citizenship behavior, especially in today's dynamic work environment. Transformational leadership involves idealized influence, intellectual stimulation, and individualized consideration. It enhances follower maturity, ideals, and concern for others, the organization, and society. Transactional leadership, while effective, may not provide sufficient job satisfaction. The full range of leadership, as measured by the Multifactor Leadership Questionnaire (MLQ), includes both transactional and transformational factors, with leaders varying in their emphasis. Transformational leadership is essential in collectivist cultures, where leaders can more easily inspire and influence followers. It is also important in diverse settings, where leaders must navigate different ethnic, racial, and gender dynamics. Research indicates that women may be more transformational than men, though this needs further study. Training and development programs can enhance transformational leadership, with a focus on individualized consideration and intellectual stimulation. Measuring transformational and transactional leadership presents challenges, including multicollinearity and the need for reliable scales. The MLQ is a key tool, though its factors may vary across cultures. Transformational leadership is linked to follower self-concept, self-esteem, and collective efficacy. Future research should explore how context affects leadership effectiveness and how followers are transformed from self-interest to group or societal concern. New methods are needed to better understand the cause-effect relationships in leadership. Overall, transformational leadership remains a vital area of study for effective organizational and societal development.