#4 Larry Ellison — Founder of Oracle

Larry Ellison was born in New York City to an unwed mother of Jewish heritage. His father was an Italian American U.S. Air Force pilot. After Ellison contracted pneumonia at the age of nine months, his mother gave him to her aunt and uncle for adoption. He did not meet his biological mother again until he was 48.

Ellison graduated from Eugene Field Elementary School in Chicago in January 1958 and attended Sullivan High School at least through the fall of 1959 before moving to Chicago's South Shore, a middle-class Jewish neighborhood.

He later dropped out of the University of Chicago after his adoptive mother died, never earning a degree, moved to California and bounced around odd jobs for eight years. But, he had learned to code back at school and that won him a contract with the CIA to build a special project code-named "Oracle." He and his co-workers finished that project a year early, leaving them time to build a commercial-facing version.

"I don't think my personality has changed much since I was 5-years-old. The most important aspect of my personality, as far as determining my success goes, has been my questioning conventional wisdom, doubting the experts and questioning authority," Ellison said in an interview with the Academy of Achievement. "While that can be very painful in relationships with your parents and teachers, it's enormously useful in life."

Read Also: 10 Hot Recently Launched Gadgets and Google, HP Halt Sales Of Chromebook 11s