This book is well-written and extremely interesting. The story begins in the late 1700s with the first twenty years of Henry Whittaker's life, as well as the entire eighty years of his daughter, the main character, Alma. They are fascinating people, and the times as well as the settings are wrought in expert detail. I was astonished at the effort Gilbert put into it.
The subtext (if not the theme) of the book is evolution, both biological and sociological, and I think the reason Gilbert went into so much detail, however well-crafted and entertaining, was to demonstrate various aspects of evolution - or the resolute lack thereof - in of each of her characters. Thus we follow the lives of Alma, her father, her mother, Prudence, the insane friend, the insane husband, the Tahitian missionary, the Tahitian missionary's son, et. al. And I'm just getting started. Even Roger the dog evolves in order to triumph at life. Okay, I'm kidding about him. Sort of.
I'm not going to describe the entire book. Plenty of other readers will do that. However, I will say that there is a transcendent scene toward the end, when Alma and another scientist/big thinker debate the evolutionary logic of altruism. I was entranced by this unanswerable question and their discussion of it. However, that was just the icing on the cake. The main takeaway of the story, for me, was that we all have a chance to live our biggest life possible, if only we try as hard as we can and never, never let ourselves weaken. It's an empowering theme. I recommend this book, with the caveat that the evolved reader manage its length by discreetly skimming, thus saving her energy for the rest of life's battles.