Well, this is supposed to be a very subjective and fun list. It can be anything from the latest mystery novel to the Atlas. Just any book you feel is the most influential, important, etc.
One of the most influential book in American society.
The theme of Atlas Shrugged, as Rand described it, is "the role of man's mind in existence." The book explores a number of philosophical themes that Rand would subsequently develop into the philosophy of Objectivism. It advocates the core tenets of Rand's philosophy of Objectivism and expresses her concept of human achievement. In doing so it expresses many facets of Rand's philosophy, such as the advocacy of reason, individualism, the market economy and the failure of government coercion.