Audrey Niffenegger's Her Fearful Symmetry is a story about two sets of twin sisters: Julia and Valentina Poole, and Elspeth Noblin and her sister, Edie Poole, mother to the younger twins.
After Elspeth dies of cancer, Julia and Valentina move from their home in Chicago into their aunt's apartment in London, a place that overlooks Highgate Cemetery. They had never known their aunt, since their mother and their aunt had remained estranged for most of the girl's lives, but they soon realize that though she is dead, Elspeth is not necessarily gone. They meet the eccentric Martin, an OCD agoraphobic creator of crossword puzzles, and Elspeth's former lover, the younger Robert, and try to decipher whether or not Elspeth is truly haunting them or if it is their imagination.
What drives the girls is what drove their mother and aunt, and, Niffenegger implies, drives most twins. That beyond their closeness and all their similarities, these are people driven to search for their own identity. There is evidence in the story that Edie and Elspeth have failed to completely disentangle their identities, and that Julia and Valentina threaten to repeat their fate. This makes what drives the girl's so desperate. As one tries to hold on to their sameness, the other pulls away, till, inspired by the ghost of her aunt, Valentina concocts a dangerous plan to forever pull away from her sister.
Crafting characters like twins in fiction can be a slippery slope. Charles Dickens entertained the trope, as did Mark Twain, but if an author is not careful, the characters can be muddled together. Casting the central protagonists as twins is dangerous for an author, but Niffenegger deftly pulls off creating different identities for Julia and Valentina. Things get a bit more convoluted with Edie and Elspeth, and at the climax of the novel, one might need to take copious notes to follow the consequences of the big twist, but an understanding of what has happened will make the subsequent events all the more heartbreaking, and will cast a devious light on a character once perceived as sad and desperate.
At the heart of this novel is Highgate Cemetery , a very real place in London. It is evident that Niffenegger researched the historical landmark extensively while crafting her story, but only because she brings to life on the page this vast collection of monuments to the reposed. If research is needed for the crafting in the story, evidence of it is best pushed far back, so that the revelation of the information is presented naturally as the story unfolds and is delivered in the narrator's voice, not as bleak quotes from a text book. Niffenegger, who lives in Chicago, even admits to working at Highgate Cemetery for a time, immersing herself in the world she creates for her readers. Follow the link at the beginning of this paragraph to visit the real cemetery and learn all about it.