It is a good book. The middle section on how to prepare a sermon is full of gold nuggets. You'll find all sorts of encouragements like this one:
"A pastorate is made up of a lot of sermons, and the fact is, most of those sermons are going to be singles rather than triples or home runs. But that's fine. If the Lord is so kind as to give you even a long string of singles, that's purely of His grace, and your congregation will benefit and grow from that. You score runs with a string of singles. So don't worry if you haven't hit a home run in a while--and if you hit one today, don't get cocky! Either way, go home, rest, thank God for the grace He gave you to teach and encourage His people again, take some time off, and then start the whole process over the next week. Our God is a good God, and week after week, sermon after sermon, He will give grace and strength and insight to the men who preach His Word."
Well, sometimes I don't even hit singles. Sometimes I'm hit by the pitch and take first base with a bit of a bruise. Anyway, that's the kind of encouragement a preacher needs.
And, the conclusion to this book is fantastic. Dever and Gilbert both include a sermon manuscript peppered with comments and questions for each other about the sermon. I commend it to those who want to grow in their preaching. You can find more info about this book here.