Motivation is derived from the Latin word 'movere' meaning 'to move' and refers to something that moves a person to action and continues them enthusiastically. Motivation theories attempt to explain what drives human behavior and the variables that comprise the motivation process. Important motivation theories discussed include Maslow's hierarchy of needs which proposes humans are motivated to fulfill physiological, safety, social, esteem and self-actualization needs in order; Herzberg's two-factor theory which distinguishes between job satisfiers/motivators and hygiene/dissatisfiers; and McGregor's Theory X and Y which present contrasting assumptions about human motivation and management styles.