I cooked from it first

I bought this expecting a cookbook and got something closer to a driving lesson.

The four chapters are the whole business and I resisted them for about forty pages, because I have a shelf of cookbooks and I didn't think I needed a theory of anything. Then I salted a chicken the night before instead of an hour before, the way she says to, and it came out of the oven a different animal. I have not gone back since. That one change has done more for my cooking than a decade of following recipes to the letter.

The acid chapter is where I properly fell in. I'd spent years making things that were fine and flat and I could never work out what was missing, and the answer turned out to be a squeeze of something at the end, nearly every time. Now there is always a lemon in the house. It's a small stupid thing and it has quietly changed most of what I cook.

The illustrations aren't decoration and I want to be clear about that — the world map of fat, where every cuisine's cooking fat sits, is the clearest single page about food I have ever seen. I've photographed it and sent it to three people, one of whom sent it on to four more.

I cooked a whole Friday out of it once, for four people, and it was the least stressed I've ever been hosting, because I finally understood what each step was actually for and could tell by tasting whether it had happened yet. Dee asked what was different and I said I salt things earlier now, which sounds like nothing and is not nothing.

Where it's weaker: the recipes at the back are good but they aren't the reason to own it, and if you came purely for recipes you'll feel a bit short changed. She also writes like somebody who already has you on side, which I find charming and my sister finds smug. My sister is wrong, but I can see the case she is making.

My copy has a tomato thumbprint on the heat chapter that has been there two years and something greasy across the section on eggs, and that feels about right to me. A clean cookbook is a sad object.

There is a television version and it is lovely and it is not this. The programme gives you Samin being delighted in four countries; the book gives you the reasoning. I watched all of it and then went straight back to the book.

Nine. Not ten because the last section sags and because I want a second volume about bread that she hasn't written. The paper copy is heavy and gets splashed and I wouldn't have it any other way.