This is the first in-depth study of Mileva Marić Einstein and her complex life-long relationship with her husband Albert Einstein. Mileva Marić was the only woman to enter the Section of Mathematics and Physics of the elite Polytechnic in Zurich in 1896. She was a person of extraordinary intelligence and talent. However, when Marić met Albert Einstein that year, her fate became bound to his life and ambition. Raised in a patriarchal Serbian family, she was willing to sacrifice her own academic career and even her visibility to the dream of achieving something even greater, together. Einstein wrote about her as an “equal” referring to “our theory,” “our paper,” ”our work on relative motion.” He also relied heavily on Mileva for emotional support at a critical time in his life. Einstein married Mileva in defiance of very strong opposition from his parents. She wasn't beautiful, she was older, she walked with a limp and she wasn't Jewish. Yet, Einstein was magnetically drawn to her independence, strength and formidable intellect during the most creative period of his entire life. As Einstein’s reputation and adulation surged so did his womanizing. Einstein’s conduct in ending their marriage was so brutal that it dismayed even their closest friends and came perilously close to destroying Mileva. Although Einstein resisted, the divorce decree awarded future Nobel Prize money to Mileva as her property. It represented a symbolic measure of recognition for her contributions to Einstein’s scientific achievements. Despite their bitter divorce, Einstein sought the comfort of her company. While sometimes touchingly considerate, Einstein was vindictive and brutal when challenged or hurt. A true understanding of Einstein as both a man and a genius, is impossible without a detailed study of the woman who loved Einstein so deeply with an emotional and intellectual bond that bore a very rare fruit. It changed our view of the universe.