The ammonites got me. Not the argument, the ammonites.

Read in a hot August in a caravan in Pembrokeshire with the gorse going off like small guns in the heat, which is a stupid setting for it and possibly the reason it went down as easily as it did.

The structure is what makes it. Thirteen chapters, thirteen species, each standing in for a mechanism. The ammonite for the asteroid. The great auk for plain slaughter. The golden frog for a fungus we carried round the world on our boots without noticing. The coral for the chemistry of the ocean changing underneath everything at once. It's a tidy plan and it works, largely because she keeps going to places and standing in them rather than assembling the thing out of papers.

The ammonites got me, and I hadn't expected them to. I know roughly what happened at the boundary; everyone does. But the part about how long it took anybody to accept that a species could vanish at all — that Cuvier had to more or less invent the idea, and that it was new and genuinely shocking when he did — rearranged something for me. We have had the concept for about two hundred years. It is younger than the chapel at the end of our lane.

Where I part from her a little is tone. She's a reporter, and reporters have a register of dry competence that I think costs her here. She goes into a cave full of dead bats, describes it accurately, and moves on to the next appointment. Twice I put the book down and thought, you were standing in it, what was it like in there? And the book had already gone.

The frog chapter is the exception and it's the best writing in the whole of it. A Panamanian hotel with tanks in the back rooms, the last ones, kept alive by people who know precisely what it is they're keeping. She lets that be exactly as bad as it is and doesn't offer anybody a way out of the room.

The final chapter, about us, and the Neanderthal business, and the idea that this is simply what our species has always done, I find less convincing than she does. It's a large claim resting on a fairly thin bench, and it has the effect of converting a long series of decisions into a destiny. Which is a comfortable thing to be told, oddly. Nobody is expected to do anything about a destiny.

Eight. Well made, properly useful, and I've cited the coral chapter twice in arguments since the spring. I don't think I'll reread it. I have kept it, though, which for me is the more honest rating.

If you only read one chapter, read the frogs.