A business entrepreneur is any individual who starts and operates a business while assuming the risks associated with any such venture (e.g., using one's own collateral in exchange for start-up financing from a lending institution). Entrepreneurship over the last thirty years has often been associated with the computer industry, as the development of early generation desktops by Andy Kay, whose Non-Linear Systems company introduced the Kaypro desktop computer, Adam Osborne, whose self-named desktop was the first home desktop on the market, and, on a far grander scale, Steve Jobs and Steve Wozniak, who developed the Apple computer, revolutionized the data processing and information industries.
While the titans of the desktop computer industry have been the most prominent to adorn the label of "entrepreneur," the moniker can be applied to many other types of businesses. One of the most important entrepreneurs in American history was Henry Ford, who revolutionized the transportation industry and American society through the development of the means of mass producing cars at a reasonably economical level. While one can certainly take issue with Ford's treatment of his labor force in the early years of the Ford Motor Company, and one can definitely take issue with Ford's sympathies with respect to the rise of Nazi Germany (he was a supporter of Adolf Hitler's theories on race and of the German dictator's broader societal policies), there is no question that Ford was a great entrepreneur.
Entrepreneurship exists in virtually every sector of economic activity. It is difficult to suggest that there is one specific field of endeavor in which it is most prominent. An argument can, however, be made for the information technology sector.