This is you on your doctor's iPad. And this is how Terry Ragon made $3.1B

Terry Ragon is the 64-year-old billionaire owner of InterSystems Corp., a Cambridge, Mass., database software company. Little known outside the niche its technology dominates, InterSystems underpins health-related information for the national health services of England, Scotland and Wales and the U.S. Department of Defense. Over the last two decades, Ragon has expanded InterSystems into the dominant player in healthcare information technology.