Kleon writes against the lone-genius myth: he argues good ideas come out of scenes rather than illuminated individuals, and that the way into a scene is to show what you are making before it is finished. The book is deliberately short, with a lot of white space and large pull quotes.
What I took from it
Teaching what you know. Explaining how something is done does not give the business away: it demonstrates judgement, which is what people actually hire. Anyone who takes the explanation and does it themselves was never going to be a client, and anyone who reads it and understands how much work sits behind it will be. This books section exists because of that idea.
And sharing the process rather than only the result. In work where the output belongs to a client and cannot be shown, the process is the only publishable thing: how decisions get made, what was discarded, what went wrong. It is also the hardest to write without sliding into a diary.
The chapter nobody quotes is the one about not becoming human spam: someone who only shows up to ask for attention stops being read. Publishing often has one requirement, that each thing published stands on its own.
What I left out
A fair amount, not because it is bad but because of who it addresses: Kleon is writing for creative people who want to be discovered, and several pieces of advice — show what you eat, collect your influences — mean little to someone selling services to companies. The platforms section aged exactly as you would expect. And it has to be said: this is an hour-long book stretched by design. The ideas fit in a long article.