About 1,400 letters written by Albert Einstein to his wives and children have been made public, suggesting the genius was often more interested in women than his relativity theory.
The 3,500 hand-written pages include letters sent by Einstein to his second wife, Elsa, and others received from his sons and two wives, Barbara Wolff of Jerusalem's Hebrew University's Einstein Archives said.
The letters, Wolff said, were willed by Einstein to his stepdaughter, Margot, and were kept sealed for 20 years after her death to protect the privacy of the individuals mentioned.
"Through the letters, we received information on the other side of Albert Einstein," said Wolff, who has read all of the letters over the past two years.
"We can see a much more human image than the sterile person presented 30 years ago in biographies," based mostly on Einstein's secretary in the 1950s, "who presented him as a genius with no personal or sex life".
Wolff said nevertheless that the newly released material shed no new light on Einstein's science , but that "if the image we had of Einstein before had three colours, now it has six."
Einstein and his first wife, Mileva, had two sons together. After their divorce he married Elsa, a cousin.
Previous biographies presented him as cold and cruel toward Mileva, but the letters now reveal that "his relations with his children and wives were filled with much more love and affection", Wolff said.
"I dreamt that Margot had married as well. I love her as much as if she were my own daughter, perhaps even more, since who knows what kind of brat she would have become (had I fathered her)," Einstein wrote to Elsa in 1924.
But the letters also reveal Einstein openly discussed with Elsa and Margot his numerous love affairs.
"It is true that M. (Ethel Michanowski, a Berlin socialite who was involved with Einstein in the late 1920s and early 1930s) followed me (to England), and her chasing after me is getting out of control," he wrote to Margot in 1931.
"But firstly I could hardly avoid it, and secondly, when I see her again, I will tell her that she should vanish immediately ... I don't care what people are saying about me, but for mother and Mrs M. it is better that not every Tom, Dick and Harry gossip about it."
In a letter dated from 1921, just one year after the experimental confirmation of Einstein' prediction of the bending of light, or relativity theory, he says "soon I'll be fed up with the relativity".
"Even such a thing fades away when one is too involved with it," wrote the German-born Einstein who died in 1995 at the age of 76.