In the first chapter he quotes Parker Palmer in Let your life Speak, (one of my favourite books)
"There is a Hasidic tale that reveals, with amazing brevity, both the universal tendency to want to be someone else and the ultimate importance of becoming one's self:Rabbi Zusya, when he was an old man, said, "In the coming world, they will not ask me: 'Why were you not Moses? They will ask me: Why were you not Zusya"
To translate, they will not ask why did you not preach like Nicky Gumbel, Dick Lucas, MLJ, John Stott, Tim Keller, Mark Driscoll or Rob Bell but why did you not preach like David Cooke.
He has a few take-outs that struck me:
1. What the text means is in large measure dependent on how it is said
2. On observation of lots of preachers, that I agree with, is a quote from Brenda Eeland about a concert pianist, 'She always practices and never plays'
3. Walter Brueggemann's three steps for exegesis; (a) a close reading of the text (b) a study of the key words and (c) discerning the text's agenda. He recommends the introduction to his Jeremiah commentary as the most helpful bit of advice he has come across.
4. The key for the preacher and in fact any reader of the bible is the question you ask. Most ask 'How? which is a question of technique and technology. You should ask 'WHY?' and that will get you on your feet on Sunday.
This one is worth having on the shelf but if you only buy one book on preaching I commend Explosive Preaching. But, as Piper notes...'you can't teach preaching you can only help' (H/T Unashamed workman)