Happy families are all alike; every unhappy family is unhappy in its own way.
Vengeance is mine; I will repay - Romans 12:19
And so begins Anna Karenina, common nominee for best novel ever written and second of Tolstoy's two major works. I read War and peace last year, and, compared to its 1400 pages, Anna Karenina seemed like a relatively small undertaking. However, it turns out that Anna's relative lack of bulk is deceiving. I found it slightly more difficult to read than War and Peace, although, surprisingly, there were a lot of common themes.
The basic plot of Anna Karenina sounds more like an episode of The Young and the Restless than the plot of one of the greatest novels ever written. Anna Karenina, the titular character, has an affair with Vronsky, a dashing, young, womanizing soldier, and the book explores her narrative alongside that of Levin, a wealthy young man searching for God. Alongside these two plots develop dozens of side characters, families, and friends. There's also a fairly involved political subplot expressing Tolstoy's derision toward many of the attitudes of the day.
Of course, in a book with this scope, any attempt to summarize the plot is going to be underwhelming. The most interesting parts of the book are those that aren't written in stone. Tolstoy steadfastly resists speechifying about the morality of his characters, choosing instead to intimately detail their thoughts so that we, the readers, can see how their reactions come about and draw our own conclusions of their morality. Even the ominous epigram (Romans 12:19) that begins the book is open to interpretation in light of the book's development. The novel itself can be read as a political treatise, a satire, a love story, a romantic tragedy, historical fiction, a mystical/religious novel, or all of the above.
Tolstoy writes the best character interactions I've read anywhere. When his characters speak, whether it's Levin and Stepan discussing politics and religion, or Vronksy and Anna having an arguement, every word and action rings exactly true. The scenes of Anna and her husband trying to function normally after her infidelity is revealed were among the most wrenching passages I've read in any book. Also worth noting is an early use of the modernist technique of stream-of-conciousness during Anna's breakdown in the penultimate section of the book.