Read in the Jonathan Cape hardback first edition.

Any new novel by McEwan is something of an event, and this is no exception. Sweet Tooth is an ambitious novel. Set in the early 1970’s, and rich with period material, the story follows a young woman, Serena Frome, in her first few months working for MI5. Sweet Tooth is the name of the operation to which she is assigned, designed to channel MI5 funding into sympathetic writers – in effect the cultural Cold War. Serena is tasked with providing funding for a supposed pro-establishment writer, without letting him know where the money is coming from. No doubt MI5 did something very similar, although the operation is plainly ridiculous, all the more vividly so when contrasted with some of her more incidental work supporting operatives under cover within the Provisional IRA.
Serena begins a relationship with the writer, Tom Haley, she is “running”, without telling him she is a “spy”. This provokes a strong reaction from one of her colleagues. Much of the novel is spent reaching this point, filling in Serena’s early love affairs, including one with a professor at her university who in later turns out, to little surprise, was leaking information to the Russians earlier in the Cold War.
Serena reads Haley’s short stories, and we are given detailed synopses of them, including extensive quotes. This gives us the stories within stories which gives the novel a complex structure. Eventually the details of the MI5 funding come out in the press, no doubt leaked by this jealous colleague, and the relationship reaches at crisis.  In the final chapter there is a revelation which reframes the rest of the narrative in a very similar way to the disclosure at the end of Atonement, and prompts the reader to look at the novel in a completely different light. This technique could be irritating – it’s not really necessary – but the successes of the novel elsewhere outweigh this distraction.
The central character appears to be an open, slightly delusional, slightly dishonest, and not very likeable character, and prior to the final chapter revelation I (and I think most readers) thought this was simply a flawed narrator of the kind we are very familiar with in much contemporary fiction. The fact that McEwan has gone further than this doesn’t I think take us anywhere particularly new – one kind of flawed perspective in a narrator is very similar to another; it is not as if we get any closer or indeed further away from “the truth”.
A couple of other moans before I try to get to why I read this novel in little over 24 hours. First, the period detail which McEwan tries so hard at getting right. The problem with this is that his trying is just too apparent – for example telling us the price of a pint of beer in 1974 (13p). Period detail needs to be accurate and appropriate, but not flaunted. Second, the plot developments, other than the final twist, and too obvious – the Cambridge don who turns out to be a spy is just a bit of a cliche, and can be seen a mile off; like-wise the boyfriend who is not just that much into sex with his hot girlfriend, who shockingly turns out to be gay. And so on. Lastly, the Monty Hall problem, which McEwan doesn’t spend too much time on, thankfully, has already been done in Mark Haddon’s “The Curious Incident” and comes across as tired here.
So why did I keep reading with such interest? McEwan’s prose style is mature and well crafted – there is rarely a false note with the language (as opposed to the plot). The central character is a bit wet and dim, always a few pages behind the reader and her associates, but is generally likeable and pleasant. Some of the period and geographic detail also struck a personal chord, and many of the other writers referenced were familiar. In itself that’s not enough to account for the interest, so I think what I am going to do is let the novel settle in my mind for a bit, maybe read some reviews and reread a few chapters, and come back to it in a few weeks.