Elizabeth Gilbert’s enormous historical novel “The Signature of All Things” covers a large portion of the eighteenth and nineteenth centuries. It centers on the remarkable Whittaker family, headed by the adventurous Henry Whittaker, an Englishman of humble beginnings who becomes the richest man in Philadelphia after accumulating significant wealth in the South American quinine trade. Alma, his intelligent daughter, inherits his wealth and intelligence and goes on to become a talented botanist. Alma develops feelings for the spiritual and mysterious Ambrose Pike, an artist, as her research explores the mysteries of evolution. This engrossing story delves into science, love, and the revolutionary concepts of a period in human history when preconceived notions were giving way to novel insights.