What are the main themes in Liar's Poker?

Capitalism and masculinity are two major themes in Liar's Poker.
Capitalism. This story thoroughly considers how the culture of Wall Street is both seductive and morally wrong. The story examines how wealth and freedom leads to childlike behavior with short term thinking. Lewis observes as his colleagues play teenage pranks, such as, blowing spitballs at one another. Lewis becomes acutely aware of what is needed to succeed on Wall Street. It is not necessarily knowledge of economics, it is instead an inner desire to exploit and intimidate others. He calls this “The Law of the Jungle.”
Masculinity. In conjunction with Lewis’ critique of capitalism is a consideration of masculinity. In a nearly all male work environment Lewis witnesses his colleagues call a phone sex line and blast the speaker on the intercom. Lewis ties this directly to masculinity when he nicknames a successful trader, “Big Swinging Dick.” He says,

If he could make millions of dollars come out of those phones, he became that most revered of all species: a Big Swinging Dick.