Dr. Leonard Leakey Hofstadter, Ph.D., is an experimental physicist at the California Institute of Technology who formerly roomed with Sheldon Cooper in Apartment 4A. Now he and his wife Penny live in that apartment. They also formerly lived in Penny's (now Sheldon and Amy's) apartment Apartment 4B. Next to Sheldon, he's the main protagonist of The Big Bang Theory. Originally from New Jersey, Leonard attended Princeton University and was twenty-four years old when he received his doctorate with a Dissertation of the Year award for experimental particle physics. Having lived with Sheldon for 1 decade as of Season 6, he and Leonard are best friends; however, Leonard can become very agitated by many of his eccentricities and often feels obligated to explain Sheldon's behavior and serve as a Mediation|mediator between him and other people in situations – he's been described as the straight man of the series. While Leonard, along with his geek friends and fellow scientists, is somewhat socially inept, Leonard would like to be better accepted outside of his social group. Leonard is better-adjusted than his companions, being more willing to try different things. He appears to be best suited as a leader of the group, with Sheldon commenting how Leonard is the "Kirk" of their landing party. The romance between him and neighbor Penny, with their on-and-off relationship has been the major force for drama until Shamy started.