With echoes of her deceased mother Mary Wollstonecraft’s avant garde feminism undergirding the narrative, Mary Godwin Shelley emerges from “The Determined Heart” as a heroine ahead of her time. Her unconventional love affair with Percy Bysshe Shelley marks a pivotal turning point in her young life, and what follows leads to myriad highs and lows and generates her crowning achievement, “Frankenstein.” Populated by characters both legendary and mundane, this story draws readers into a world that is in many ways reflective of contemporary society, and although it is a work of historical fiction, it nevertheless imparts a stimulating view of classic literature and the lives of those who composed it, tempestuous relationships and all. Short chapters and a continuous pace make this a relatively quick read, as well.