In his book, The Human Side of Enterprise, Douglas McGregor (1960) proposed two theories by which employee motivation can be viewed. He called the theories, Theory X and Theory Y. Both of these theories are based on the premise that management’s role is to assemble the factors of production, including people, for the economic benefit of the firm. Beyond this point, the two theories of management diverge. Essentially, Theory X assumes that people work only for money and security, whereas Theory Y proposes that not only money and security, but also self-actualization and intrinsic rewards drive individuals to achieve their goals.