Dr Erasmus Darwin seemed an innocuous Midlands physician, a respectable stalwart of eighteenth-century society. But there was another side to him.

Botanist, inventor, Lunar inventor and popular poet, Darwin was internationally renowned for breathtakingly long poems explaining his theories about sex and science. Yet he become a target for the political classes, the victim of a sustained and vitriolic character assassination by London's most savage satirists.

Intrigued, prize-winning historian Patricia Fara set out to investigate why Darwin had provoked such fierce intellectual and political reaction. Inviting her readers to accompany her, she embarked on what turned out to be a circuitous and serendipitous journey.

Her research led her to discover a man who possessed, according to Samuel Taylor Coleridge, 'perhaps a greater range of knowledge than any other man in Europe.' His evolutionary ideas influenced his grandson Charles, were banned by the Vatican, and scandalized his reactionary critics. But for modern readers, he shines out as an impassioned Enlightenment reformer who championed the abolition of slavery, the education of women, and the optimistic ideals of the French Revolution.

As she tracks down her quarry, Patricia Fara uncovers a ferment of dangerous ideas that terrified the establishment, inspired the Romantics, and laid the ground for Victorian battles between faith and science.