Jeanne Theoharis was as surprised as anyone to learn that Rosa Parks鈥 work as civil rights activist extended far beyond that fateful day in 1955 when she refused to give up her seat on a Montgomery, Ala. bus. But when Parks died nearly seven years ago, Theoharis started doing some digging and discovered that there was much more to Parks鈥 story.

Forced to leave Montgomery in 1957 because of death threats and the inability to find work after the bus boycott, Parks spent the second half of her political life in Detroit battling the racism of the North. And yet, in all the public tributes to Parks, there was little mention of this half century of activism.

鈥淏izarrely, the story hadn鈥檛 been told,鈥 says Theoharis, a professor in the Department of Political Science, who has penned several books and articles on the Civil Rights and Black Power movements. 鈥淪he is one of the most famous women of the 21st Century and there was no scholarly biography.鈥

Theoharis says the reason for this is threefold. 鈥淏ecause Parks was so famous, many of us assume we know everything about her. Also, a lot of people with progressive or radical politics tend to be in your face; Parks didn鈥檛 have that kind of personality.鈥 Finally, Theoharis adds, Parks鈥 personal papers have been tied up in legal disputes over her estate, which presents an obstacle to any scholar hoping to embark on a comprehensive biography.

But Theoharis wasn鈥檛 deterred. She poured over old newspapers, magazines, and the archives of the (NAACP) and other civil rights organizations. She also interviewed family members and those who worked with Parks.

Theoharis鈥 research eventually turned into (Beacon, 2013), a revealing book about a life that was devoted to helping end segregation and injustice way before that day on the Montgomery bus. The book will be released on January 29, in time for what would have been Parks鈥 100th birthday on February 4.

Theoharis structures the text chronologically, starting with Parks鈥 childhood in Alabama, followed by her marriage, a decade of work with the Montgomery branch of the NAACP鈥攁 chapter that was considered radical at the time鈥攁nd then on to her bus arrest, the boycott, and what Theoharis calls 鈥渢he decade of suffering that ensued,鈥 which included health problems, death threats, and financial insecurity.

The book also chronicles Parks鈥 life after the boycott, when she moved to Detroit with her husband and eventually found work with a young Rep. John Conyers, who had recently been elected to the U.S. Congress. The Rebellious Life of Mrs. Rosa Parks also explores the civil rights icon鈥檚 later work as a picket-line protestor and featured rally speaker with the anti-Vietnam and anti-Apartheid movements.

鈥淭here鈥檚 no doubt her act that day in Montgomery was courageous. It just wasn鈥檛 the first time she had done this kind of thing,鈥 says Theoharis, who adds that Parks had routinely refused to pay her fare in the front of the bus and enter in the back, as was the law at the time, and had been kicked off the bus before. She had also refused to use the 鈥渃olored鈥 drinking fountain.

鈥淪he knew full well how dangerous it was to do what she was doing,鈥 says Theoharis. 鈥淭here was a real threat of violence and no sense that one might possibly accomplish anything for it. She had no idea that this would galvanize a movement.鈥

But Parks was just the right mix of working-class woman with a 鈥渕iddle-class demeanor,鈥 as Theoharis describes it, that the NAACP leadership could work with. Her history of activism gave the organization faith that she wouldn鈥檛 flinch under pressure and that she was perfect person to see through a court case challenging the legality of racial segregation.

The work Parks would go on to do, like participating in the Poor People鈥檚 Campaign after Martin Luther King, Jr. was assassinated, would touch on some of the biggest civil and human rights campaigns of the last century.

鈥淗er story is almost like the movie 鈥楩orrest Gump鈥 in that she ends up taking part in all these historical events,鈥 says Theoharis. 鈥淪he had this huge political lifespan and yet what we know about her too often focuses on this one day.鈥

There鈥檚 no doubt Parks is seen as an icon, but if history told a more complete story, Theoharis thinks she would be much more relatable, and useful, to young people.

鈥淚f we look at the real substance of her politics, it provides a deep challenge to us in terms of what individual courage looks like,鈥 she says. 鈥淎nd it becomes much easier to see how we work for social change today.鈥