A half-century after announcing his theory of relativity, physicist Albert Einstein died in Princeton, New Jersey, the small university town that had been his home for the last 22 years of his life.
A ruptured artery in his stomach caused him to bleed to death at the age of 76 on April 18, 1955.
Shortly afterward, all bodily traces of the most famous scientist in history disappeared. A pathologist at Princeton's municipal hospital took his brain and hid it away for decades, while his stepdaughter, Margot, spread his ashes over a secret place in accordance with his wishes.
The two executors of his estate, his friend Otto Nathan and his secretary Helene Dukas, went through letters and documents in his house on Princeton's Mercer Street and in his laboratory at the Institute for Advanced Studies (IAS), destroying anything that posthumously could have soiled the image of the man German physicist Max Planck called "the new Copernicus."
What remained were Einstein's revolutionary findings, beginning with the theory of relativity, announced in 1905, and quantum theory, for which he won the Nobel Prize for Physics in 1921, followed by his correspondence as a Jew, a leftist, a pacifist and a radical thinker and his written exchanges with prominent colleagues and friends.
Inevitably, people wanted to know more about the 20th century's top genius. Initially, Nathan and Dukas stood in the way. When his daughter-in-law found a stack of early love letters and wanted to publish a book about them, Einstein's executors got a court order to stop it.
But in subsequent efforts, Nathan and Dukas had to accept that the light would eventually fall onto Einstein's shadier side.
Dozens of historians, researchers and authors have done extensive detective work to unlock the secrets of the man born in Ulm, Germany in 1879. Among his biographers is astrophysicist Stephen Hawking, himself an icon in the world of science. His sister Maja and son-in-law Rudolf Kayser also have written about his life.
Inivestigation into Einstein's life has uncovered vibrant details of an active love life and unknown facets of his personality. In addition to sons Hans Albert and Eduard, a daughter, Liserl, was born to Einstein and his first wife, Serbian mathematician Mileva Maric, who may have also contributed to his developing the theory of relativity.
The girl, a Down's syndrome baby born before the couple was married, either died early or was given up for adoption because of young Einstein's demanding career, according to Neffe. When Einstein fathered another daughter, Evelyn, late in life with a New York dancer, Einstein's son Hans Albert stepped in and raised the girl, never divulging her biological parents.
Einstein divorced twice on unfriendly terms. To his first wife he revealed a cold-heartedness that bordered on brutality. According to recent research by Evan Harris Walker, a physicist, and Senta Troemel-Ploetz, a German linguist, Mileva may have contributed to the development of Einstein's major ideas on relativity and done the mathematics that made it possible.