What is the main conflict in Black Pioneers of Science and Invention by Louis Haber?

"Black Pioneers of Science and Invention" by Louis Haber is a work of nonfiction designed to introduce the inventions and contributions of fourteen African American men dating from the 18th to 20th centuries. The accomplishments range from engineering to medicine and beyond. Haber points out that while the inventions of these pioneers are internationally known, the scientists themselves are all but forgotten.