Hearon used a special technique for the Jordan book. She alternated chapters, from Jordan's autobiographical voice to the writer's voice, third person, filling in historical background. The transition from fiction to collaborating can be tough. It was enough to live on while she wrote that book, but it didn't pay for her next work of fiction, as she had hoped. Hearon spent a year on the Jordan book, working 14-hour days for the last five months.
Nonfiction sells more than fiction too.
Barbara Jordan was also syndicated by the Los Angeles Times, which helped to make Hearon better known. As a result, she was asked to give writing workshops, speeches, and readings. If you just write fiction, you have a more limited vita, a more limited way to present yourself. I made a lot of contacts from the Jordan book.