Early Life and BackgroundThe eldest of Frank and Isobel Hawking's four children, Stephen William Hawking was born on the 300th anniversary of the death of Galileo—long a source of pride for the noted physicist—on January 8, 1942. He was born in Oxford, England, into a family of thinkers. His Scottish mother had earned her way into Oxford University in the 1930s—a time when few women were able to go to college. His father, another Oxford graduate, was a respected medical researcher with a specialty in tropical diseases.

Stephen Hawking's birth came at an inopportune time for his parents, who didn't have much money. The political climate was also tense, as England was dealing with World War II and the onslaught of German bombs. In an effort to seek a safer place, Isobel returned to Oxford to have the couple's first child. The Hawkings would go on to have two other children, Mary (1943) and Philippa (1947). And their second son, Edward, was adopted in 1956.

The Hawkings, as one close family friend described them, were an "eccentric" bunch. Dinner was often eaten in silence, each of the Hawkings intently reading a book. The family car was an old London taxi, and their home in St. Albans was a three-story fixer-upper that never quite got fixed. The Hawkings also housed bees in the basement and produced fireworks in the greenhouse.

In 1950, Hawking's father took work to manage the Division of Parasitology at the National Institute of Medical Research, and spent the winter months in Africa doing research. He wanted his eldest child to go into medicine, but at an early age, Hawking showed a passion for science and the sky. That was evident to his mother, who, along with her children, often stretched out in the backyard on summer evenings to stare up at the stars. "Stephen always had a strong sense of wonder," she remembered. "And I could see that the stars would draw him."

Early in his academic life, Hawking, while recognized as bright, was not an exceptional student. During his first year at St. Albans School, he was third from the bottom of his class. But Hawking focused on pursuits outside of school; he loved board games, and he and a few close friends created new games of their own. During his teens, Hawking, along with several friends, constructed a computer out of recycled parts for solving rudimentary mathematical equations.

Hawking was also frequently on the go. With his sister Mary, Hawking, who loved to climb, devised different entry routes into the family home. He remained active even after he entered University College at Oxford University at the age of 17. He loved to dance and also took an interest in rowing, becoming a team coxswain.

Hawking expressed a desire to study mathematics, but since Oxford didn't offer a degree in that specialty, Hawking gravitated toward physics and, more specifically, cosmology.

By his own account, Hawking didn't put much time into his studies. He would later calculate that he averaged about an hour a day focusing on school. And yet he didn't really have to do much more than that. In 1962, he graduated with honors in natural science and went on to attend Trinity Hall at Cambridge University for a PhD in cosmology.

ALS DiagnosisWhile Hawking first began to notice problems with his physical health while he was at Oxford—on occasion he would trip and fall, or slur his speech—he didn't look into the problem until 1963, during his first year at Cambridge. For the most part, Hawking had kept these symptoms to himself. But when his father took notice of the condition, he took Hawking to see a doctor. For the next two weeks, the 21-year-old college student made his home at a medical clinic, where he underwent a series of tests.

"They took a muscle sample from my arm, stuck electrodes into me, and injected some radio-opaque fluid into my spine, and watched it going up and down with X-rays, as they tilted the bed," he once said. "After all that, they didn't tell me what I had, except that it was not multiple sclerosis, and that I was an atypical case."

Eventually, however, doctors did inform the Hawkings about what was ailing their son: He was in the early stages of amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease). In a very simple sense, the nerves that controlled his muscles were shutting down. Doctors gave him two and a half years to live.

It was devastating news for Hawking and his family. A few events, however, prevented him from becoming completely despondent. The first of these came while Hawking was still in the hospital. There, he shared a room with a boy suffering from leukemia. Relative to what his roommate was going through, Hawking later reflected, his situation seemed more tolerable. Not long after he was released from the hospital, Hawking had a dream that he was going to be executed. He said this dream made him realize that there were still things to do with his life.

But the most significant change in his life was the fact that he was in love. At a New Year's party in 1963, shortly before he had been diagnosed with ALS, Hawking met a young languages undergraduate named Jane Wilde. They were married in 1965.

In a sense, Hawking's disease helped him become the noted scientist he is today. Before the diagnosis, Hawking hadn't always focused on his studies. "Before my condition was diagnosed, I had been very bored with life," he said. "There had not seemed to be anything worth doing." With the sudden realization that he might not even live long enough to earn his PhD, Hawking poured himself into his work and research.

Research on Black HolesGroundbreaking findings from another young cosmologist, Roger Penrose, about the fate of stars and the creation of black holes tapped into Hawking's own fascination with how the universe began. This set him on a career course that reshaped the way the world thinks about black holes and the universe.

While physical control over his body diminished (he'd be forced to use a wheelchair by 1969), the effects of his disease started to slow down. In 1968, a year after the birth of his son Robert, Hawking became a member of the Institute of Astronomy in Cambridge.

The next few years were a fruitful time for Hawking. A daughter, Lucy, was born to Stephen and Jane in 1969, while Hawking continued with his research. (A third child, Timothy, arrived 10 years later.) He then published his first book, the highly technical The Large Scale Structure of Space-Time(1973), with G.F.R. Ellis. He also teamed up with Penrose to expand upon his friend's earlier work.

In 1974, Hawking's research turned him into a celebrity within the scientific world when he showed that black holes aren't the information vacuums that scientists had thought they were. In simple terms, Hawking demonstrated that matter, in the form of radiation, can escape the gravitational force of a collapsed star. Hawking radiation was born.

The announcement sent shock waves of excitement through the scientific world, and put Hawking on a path that's been marked by awards, notoriety and distinguished titles. He was named a fellow of the Royal Society at the age of 32, and later earned the prestigious Albert Einstein Award, among other honors.

Teaching stints followed, too. One was at Caltech in Pasadena, California, where Hawking served as visiting professor, making subsequent visits over the years. Another was at Gonville and Caius College in Cambridge. In 1979, Hawking found himself back at Cambridge University, where he was named to one of teaching's most renowned posts, dating back to 1663: the Lucasian Professor of Mathematics.