What I got was The Secret History re-worked, with a different theme and different relationships between the characters all leading to the same conclusion. Where The Secret History was about hubris and isolation and selfishness, The Likeness is about... well, it is about selfishness, to an extent, but it's not the same kind of selfishness as in The Secret History. It's about love, about belonging, about permanence, about forever and what that idea does to you, why we seek it and why we avoid it. The whole sticky question of identity, and how the girl called Lexie shaped herself into everything that everyone else wanted her to be: how all she ever needed to feel safe was the knowledge that she could leave whenever she wanted.
Daniel is Henry; Justin is Francis. Rafe is Charles, and Lexie is his Camilla but Abby is Daniel's. Cassie, the outsider with the face of the insider, is Richard-Lexie-Camilla all at once. She's even Bunny, as the victim, and yet not, because Bunny is killed by resentment and humiliation and lasting nager, whereas Lexie dies because her friends love her (too much, perhaps?).
The Likeness is about what happens when you build yourself a family and then leave it hanging in space and hand over all responsibility for the maintaining of it to another member of the group. It's about finding people who fit you, and how they can both help you better than anyone else can and hurt you more than anyone. It's about illusions too, and how far we'll go to hang on to them. It's even about history: Daniel's ancestor kills the girl he loves because he thinks her child will turn out to be a fairy changeling, and Daniel destroys his family in an attempt to keep it. You get the feeling it's a fault in his family line, a kind of inability to actually trust the people he loves, history repeating itself in a twisted way.
(In a weird crossing of the wires in my brain it makes me think of that moment in Star Wars when Leia says to Tarkin that the more you tighten your grip, the more star systems will slip through your fingers. Yeah.)
Two other things stay with you long after you're done reading: one is Whitethorn House itself, the scene of the action, where Lexie and her friends lived: it's an enchanted little island outside of time and the rest of the world, and you really, really want to have been there. You want to live there, to walk in the garden and read in the library and help sand the floors and - honestly, I think it might be my favourite imaginary house ever (outside of Middle-Earth, at any rate).
The other thing is Cassie herself. She's such a great character: traumatised but keeping her feet, struggling to understand Lexie with this kind of desperation, as if insight into her doppelganger means insight into herself (although at the end, she's faced with a decision similar to Lexie's, and chooses very, very differently); her relationship with fellow cop Sam O'Neill is calm and supportive and touching, even when she's a confused mess and he's no bettter, and her relationship with Frank Mackey, her former boss, is refreshingly free of anything like UST, a kind of halfway house between boss and subordinate, old friends and old rivals. Strong, smart, quick on her feet, manipulative, passionate and healing and very smooth, I really loved her.
In short: it's the kind of book that gets its claws in you and won't let go, full of interesting characters, haunting places, clever, not very exciting, but then it's not really supposed to be: the tension isn't in the actions of the characters but their emotions. If you've read The Secret History, don't be put off by the parallels; they're the stuff that lit class papers are made of, I think. I really, really liked this one.