Mary Ellen Pleasant may not be a household name, but her story rivals that of any great American entrepreneur. In the 1800s, Pleasant became one of the first African-American female self-made millionaires in the U.S. despite the significant obstacles she faced as black woman.Pleasant employed her inherent savvy, building a massive investment portfolio that was reportedly worth as much as $30 million at one time — a fortune that would make her close to a billionaire in today’s value“I often wonder what I would have been with an education,” Pleasant said in an autobiography published in 1902. “I have let books alone and studied men and women a good deal.”