How good this novel is can be demonstrated by its opening line: ""My name is Serena Frome (rhymes with plume) and almost 40 years ago [the early 1970's] I was sent on a secret mission for the British security service. I didn't return safely. Within eighteen months of joining I was sacked, having disgraced myself and ruined my lover, though he certainly had a hand in his own undoing." Yes, it's a "spy novel" in some sense; however only very loosely so. Too much said about the plot will ruin the effect for the reader though. I can say that the book is full of irony and simply wonderful.
Serena is one of the best characters that I've ever met in literature. She is so complex. As we meet her, we learn that she has gone to college at Cambridge (not too shabby) where she studied math after being forced to do so by her ambitious mother (instead of English and literature, which were Serena's passions and still are when we meet her - she literally can ingest one or two books a day on average and is a voracious and passionate reader). So, in many ways, this is a book about books and writing - it's also about inexperience/innocence, jealousy and relationships, betrayal and deceit. More so, it is about whether literature is still a valuable tool in modern society and whether books read as deeply as McEwan believes that they should be read will disappear.
McEwan, as usual, is a wonderful writer. This book brought me comfort in the way that a satisfying stew or roast could - it was something that I could sink my teeth into and savor and left me feeling satisfied and thoughtful in a pleasant way. His narrator is cheeky, warm, animated and intimate - we are allowed to see parts of her life that not everyone can see or would normally see. It's like we're eavesdropping on her conversations or reading her diary. As such, this novel was delightful and sublime.