Just wrote this for a student and thought it might interest you:

To my mind, an author is like a tour bus driver.  We have tons of these tour buses in LA.  The driver has to double as guide.  His or her job is to drive the bus while pointing out the sights and telling interesting anecdotes or details about them to make them memorable and meaningful to the passengers.  Those passengers will never witness sights that the bus doesn’t pass, and won’t remember which sights are significant unless the driver/guide tells a good story or makes a good association around them. The skill of the driver in setting a course, speeding up or slowing down as necessary, keeping the vehicle safely in motion, and delivering resonant information in an entertaining and engaging way will determine what the passengers take away from the tour – or whether their minds wander off into boredom midway through the ride.

Likewise, an author’s job is to drive and guide the vehicle of narrative in such a way that the reader is picked up by the very first promising line and then rides effortlessly through the maze of ideas, turning and pausing with enough time to absorb the sights, and emerges at the end of the ride having had the meaningful experience that the driver intended.  If the driver loses or ejects the rider anywhere along the line, the writer has failed. And the reader/rider cannot be expected to notice or understand sights that the writer/guide has not passed or described in an engaging, memorable, and meaningful way.