1: Sir Isaac Newton (1642 - 1727)

­With numerous and far-reaching contributions to ph­ysics and mechanics, Sir Isaac Newton is universally known as a brilliant thinker. Indeed, polls of both scientists and the public show an agreement that Newton even surpasses Einstein in influence [source: The Royal Society]. Some of his notable contributions include inventing calculus, explaining "universal gravitation," developing laws of motion and building the first reflective telescope.

Despite his many achievements, Newton suffered from psychotic tendencies and mood swings (including wildly enthusiastic periods), and he was often difficult to get along with [source: Encyclopedia Britannica, Salas]. Hershman and Lieb also theorize in their book that Newton probably suffered from bipolar disorder [source: Stamp Out Stigma]. In addition, his delusional letters lend credence to the theory that he was schizophrenic [source: Glover]. Newton's father died before he was born, and he was separated from his mother between the ages of two and 11. His mental disorder might have been a result of this prolonged traumatic childhood experience [source: Encyclopedia Britannica].

To learn more about geniuses and other topics, go on to the next page.