Correct in its mechanisms, and forty years out of date in its examples.

Four sittings, about five hours, and I finished it faster than I meant to; the mechanisms are genuinely well identified and each one gets a name I have been able to keep hold of since. Reciprocity, commitment, social proof, liking, authority, scarcity. Six labels for things I have watched happen in meeting rooms since 1974 without ever having a word for them.

The trouble is the evidence. Almost every case is a car showroom or a charity envelope from the early eighties, and the world it describes had far fewer doors to knock on than ours does. He is describing a mechanism through examples that have since been automated, and he can't help that, but a reader in 2026 has to do a lot of the translating himself.

The commitment chapter is the one that got me. Not long after reading it I sat through a double-glazing pitch and recognised the sequence as it was being run on me: the small agreement, then the slightly larger one, then the assumption that the thing was settled. I let it continue out of curiosity. I bought the windows. They're perfectly good windows.

A seven. Read the first half, then look up whether the studies have held; several have not, and he is not the one who will tell you.