Leadership is both a research area and a practical skill, regarding the ability of an individual or organization to "lead" or guide other individuals, teams, or entire organizations. Controversial viewpoints are present in the literature, among Eastern and Western approaches to leadership, and also within the West, on US vs. European approaches. In US academic environments leadership is defined as "a process of social influence in which a person can enlist the aid and support of others in the accomplishment of a common task". Leadership seen from a European and non-academic perspective encompasses a view of a leader who can be moved both by communitarian goals but also by the search for personal power. As the European researcher Daniele Trevisani states:

"Leadership is a holistic spectrum that can arise from: (1) higher levels of physical power, need to display power and control others, force superiority, ability to generate fear, or group-member's need for a powerful group protector (Primal Leadership), (2) superior mental energies, superior motivational forces, perceivable in communication and behaviors, lack of fear, courage, determination (Psychoenergetic Leadership), (3) higher abilities in managing the overall picture (Macro-Leadership), (4) higher abilities in specialized tasks (Micro-Leadership), (5) higher ability in managing the execution of a task (Project Leadership), and (6) higher level of values, wisdom, and spirituality (Spiritual Leadership), where any Leader derives its Leadership from a unique mix of one or more of the former factors".