The business world knows quite well who Sheldon Adelson is -- the eighth richest American who has alternately lost and recouped tens of billions of dollars in the casino business over the last few years. A wider public came to know him when two $5 million checks signed by Adelson bolstered Newt Gingrich's faltering presidential campaign earlier this year, threatening to upend the Republican primary race. But only one was signed by Sheldon. The other: Miriam.
 
While she is much less well-known than her husband, Miriam Adelson is not your average billionaire's wife. Rather, she is an accomplished medical doctor, as well as her husband's partner in a range of business and philanthropic activities. As the dynamics of the race shift, what has become clear is that this driven and passionate pair is bound to have an influence on the 2012 campaign. On Monday, The Wall Street Journal reported that they were quite possibly preparing to shift their backing to Romney -- they seem prepared to support any Republican in their hope of seeing Barack Obama defeated this fall. And Gingrich is in no way the only recipient of their largesse so far -- according to the Center for Responsive Politics, the couple ranks second in individual contributions to parties, federal candidates, and PACs in the current election cycle. They also spent $30 million during the 2008 election. Indeed, in an exclusive interview with Fortune, Dr. Adelson emerges as no less accomplished — or powerful — than her larger-than-life spouse.
 
Israeli-born Miriam Ochshorn, 66, has been married to 78-year old Adelson since 1991, and the couple has four children together. Her parents, Menucha and Simha Farbstein, fled Poland in the run-up to the Holocaust, settling in Haifa. There her father ended up owning a handful of movie theaters, though the family didn't have a television until Miriam was 16. Her husband comes from equally modest beginnings -- the son of a Boston taxi driver, Sheldon Adelson grew up in a one-room tenement in Boston's Dorchester section.
 
Dr. Miriam Adelson -- known as Miri to her friends -- earned a Bachelor of Science in Microbiology and Genetics from the Hebrew University of Jerusalem. During her two years of military service in Israel, she worked in the biological research department, and followed that by earning a medical degree from Tel Aviv University's Sackler Medical School. She went on to become the chief internist in an emergency room at the Rokach Hospital in Tel Aviv. In 1986, she served as an associate physician at Rockefeller University in New York, where she studied chemical dependency and drug addiction, with a specific focus on the spread of HIV among drug addicts. Her mentor was Mary-Jeanne Kreek, the researcher credited with discovering that methadone was a safe treatment for addicts. The two women have since collaborated on studies of methadone and addiction for the last 25 years.