Mileva Maric, an aspiring physicist, age 21, met Albert Einstein at the Swiss Federal Institute of Technology in Zurich when he was 17. They became lovers, had an illegitimate daughter in 1902, then married. In 1905, Einstein published 3 papers in a single issue of the journal Annalen der Physik. The theory of relativity was among them. He became famous, she became a housewife raising two sons. (The daughter disappeared.) They separated in 1914 and eventually divorced. He promised her his future Nobel Prize money as alimony, remarried and went to America. One son died in a mental insitution, the other became an engineering professor. Mileva died in 1948 without having published a single paper.
In 1987, his letters to her were published. Some of the language in the letters makes them sound like research partners. "How happy and proud I will be when the two of us will have brought OUR WORK on the relative motion [relativity] to a victorious conclusion!"
Einstein never explained where he got the theory of relativity. The Swiss Polytechnic was the M.I.T. of Central Europe, so Mileva had to have more than a little competence to get in, especially as a woman.
Another piece of evidence comes from Mileva's biography written by Abram Joffe, a Russian physicist now dead. He claims to have seen the original 1905 papers and said they were signed Einstein-Maric. If this is true, were these the only ones she signed?
The essayist (Dennis Overbye) goes on to say:
"Every revolution has its limits. Einstein was an ordinary man. He could see past space and time, yes, but not sex. Not all Einstein's learning nor his liberalism could keep him from making of Mileva what every other man made of his woman: a housewife, helpmate and addendum to his own identity."