Dr. Stephen Strange was originally an accomplished, but arrogant surgeon who suffered subtle, but profound neurological damage in an auto accident. Unable to continue his profession and too proud to accept another medical assignment, he quickly became unemployed and destitute. He learned of an old hermit called the Ancient One who could have the ability to cure him. Strange sought him out and asked for his aid, the old man refused, but offered to take him on as an apprentice. Strange refused, but could not leave immediately due to a sudden blizzard.
While staying for the duration, he saw the Ancient One's current apprentice, Baron Mordo, secretly attack his teacher with some mystically summoned entities. Although Strange saw the old man easily fight them off, he still confronted Mordo about his treachery and promised to inform his master. Mordo retaliated by casting restraining spells which kept Strange from both warning the wizard or attacking Mordo physicially. Amazed by these displays of magic, alarmed by Mordo's evil and the peril the Ancient One was in, but frustrated by the mystic restraints, Stephen Strange underwent a profound change of heart. Deciding the only way to stop Mordo was to learn magic himself so he could challenge Mordo on his terms, he accepted the Ancient One's offer of apprenticeship. Pleased by Strange's acceptance and the unselfish reason for it, the Ancient One accepted him and immediately removed the mystic restraints. The wizard explained that he was well aware of Mordo's treachery, but preferred to keep the villain so he could control him.
Eventually, Strange learned well and eventually took the Ancient One's place as Sorcerer Supreme of Earth, the chief wizard of his dimension and responsible for defending it from other mystic threats.
The comic quickly distinguished itself with the unique visuals of Steve Ditko with the bizarre other realities that the wizard often ventured into. After Ditko's departure, the character has had a spotty publishing history both with his own series and the leader of his own superhero team, The Defenders. Currently, he is chiefly used as a supporting character as a wizard other Marvel superheroes turn to for matters concerning magic and the supernatural.