One simple sentence gets to the heart of his technique: "Curiosity is a closer friend than creativity."
Donnellan says the mistake is trying to "be" creative.
It means you're looking inside your head for the answer, when it's not there.
Instead he tells actors to look outside themelves – to find rather than invent.
To discover what is already there outside – what the character they're playing might see if they were looking at the target of their actions through the character's eyes.
When we set out to find things that are already there, we take the important first step in the creative process.
To illustrate what he means, Donnellan talks about an actor, Irina, who is playing Juliet and struggling to work out how to play the most famous scene in Romeo and Juliet.
He says she shouldn't try to be creative in coming up with a way to say "Romeo, Romeo, wherefore art thou Romeo?" and imagine all the things she might do from the sum total of infinity.
Instead it's far more helpful for Irina to rely on her curiosity.
She just needs to open her eyes and see the target she's addressing – presumably an imaginary Romeo.
She needs to see what this imaginary Romeo is already doing – because it's what Romeo is doing that makes Juliet do things.
She sees Romeo doing something and she tries to change what he's doing – she focuses out on the target and how to change it, rather than focusing internally.
Maybe she sees a Romeo who is defending his identity – insisting that his name is as much a part of him as his body.
So she has to interrupt him, contradict him, change him: everything she does is an active reaction to something that is already occurring elsewhere.
Donnellan says: "Let Irina find rather than invent. Let her imagine that the decisions have already been taken; she only has to discover them. Again, curiosity is a closer friend than creativity.
If she sees what Romeo is doing she will respond spontaneously – she will know how to ask Romeo why he's called Romeo.
Donnellan says: "Renouncing creativity seems heresy to the artist . However, trying to be creative is disastrous."
He says: "Of course all human beings are creative, but our creativity is a symptom and not a cause.
"We do not control our own creativity, any more than we can control our feelings. We can, however, control what we do."
Elsewhere in the book Donnellan talks about the importance of paying attention and why attention is different from concentration.
He says: "Attention is about the target; concentration is about me. If I concentrate hard on an external object, or if I concentrate very hard on another person, something strange happens.
"I gradually see that other less and less and wind up seeing how I see the other person. In other words, it ends up being about me."
We choose what we concentrate on – but we can't control attention; it has to be found.
His advice to the actor is to "see" things attentively – not to "look at" things.
"Seeing implies that what is seen will have freedom to surprise me, to be different from what I expected."
The advice is invaluable whether you're playing Juliet, writing a book or trying to come up with a new business idea.
The "new" thing you're looking for is out there waiting to be discovered. You can't create it.
But if you harness your curiosity and pay attention ... you'll see it.