In addition to being considered one of the world's greatest inventors, another interesting fact about Thomas Edison is that he was famous for his dislike of sleep. Edison is also known for being incredibly strict with both his potential employees and his family.
Edison's hated sleeping because he felt it was a leftover from prehistoric times. This caused him to train himself to function on as little as four or five hours of sleep per night. Of course, his invention of the light bulb helped to make this even easier.
Edison was fierce about his intellect and well-known for his disdain of people with lower intelligence. He even went so far as to criticize his first wife's intelligence in her diary. Before hiring an employee, Edison would require candidates to take a test with over 150 questions so that he could judge their knowledge of many different areas. Out of the 500 or so people that took these tests, only 35 are said to have passed.
This strictness also applied to his children, as he famously refused to let either of his sons use his last name. His lawyers threatened to sue his oldest son Thomas Jr. to prevent him from using his own legal surname. He also prevented his youngest son, William, from opening up an auto mechanic shop called Edison Garage.