Dr. Jack Shephard is a former spinal surgeon and was the de facto leader of the survivors following the crash of Oceanic Flight 815. Jack had control issues and trouble dealing with situations that he couldn't fix. However, this ability to solve problems through reason made him able to function well during a crisis and lead several A-Missions. He was commonly looked upon as the leader of the survivors and was on good terms with everyone, especially Kate and Juliet. Jack and five other survivors managed to escape the Island by using a helicopter from the freighter, although they were forced to leave everyone else behind when Ben moved the Island. Since the rescue, Jack learned of his family relation to Claire and Aaron, laid his father to rest and became engaged to Kate. Unfortunately, certain events, including a visit from Jeremy Bentham and visions of his father, caused his resolve to collapse. A broken man addicted to pills and alcohol, Jack flew every week in the hopes his plane would crash and he would find his way back to the Island so he could fix all the bad things that had been happening there and rescue everyone left behind. However, Ben informed him that the Island wouldn't let him come alone; all of them had to go back, including the late Bentham, who was actually John Locke. Jack later returned to the island after being thrown through time and space when Ajira Flight 316 flew over the Island. He worked for the DHARMA Initiative as a workman where he tried to change the past by detonating a hydrogen bomb. His fate is currently unknown.