Dr. Barton "Bart" Hamilton was Harry Osborn's psychiatrist. While treating Harry, he came up with idea of writing a thesis about the criminal mind. Being able to hypnotize Harry, he was able to learn the entire history of the Green Goblin. After finding the secret hideout of the Green Goblin, he was able to access all of the Goblin's equipment and began experimenting with them. Feeling the sense of power that came with them he felt that he was the one who should lay claim to the Green Goblin.