It has been five years since the introduction of Dolen Perkins-Valdez to the literary world. “Wench,” her debut novel, hit the New York Times Bestsellers List in the winter of 2011 to the drumbeat of both spectacular reviews and the savvy use of what were then fledgling marketing tools, Twitter and Facebook. Since that time she has written the foreword to Solomon Northup’s “Twelve Years a Slave,” the wrenching story of a free black man kidnapped and sold into slavery, and her second novel, “Balm,” the tale of three people, post-Civil War, searching for healing, has just been released. Perkins-Valdez is an academic’s academic. A Harvard graduate, she loves the quest, the probing, almost as much as the writing. Her ability to transform well-researched slivers of a country’s pained history into rich, impassioned stories of loss, triumph and community makes her a powerhouse within the sub-genre of historical fiction.