As writers of fiction and narrative nonfiction, we are constantly seeking fresh conceptual handholds by which to remember and grasp the time-tested basics of storytelling. Many helpful analogies have been offered. Here is one of my own.
Picture the ocean in side view, a cutaway that reveals successive layers, distinct currents in motion, from the waves traveling at the surface, to the shallow flows that carry small fish along, then down through the middle ranges, each with its own separate conveyor belt of momentum, and finally to the very bottom current, the slowest, known as the submarine river.
A successful piece of narrative prose, too — especially a rich novel or memoir — operates at multiple, complementary levels, each conferring energy in its own way to the reading experience as a whole:
At the surface, like waves, the language itself must be lively and forward-leaning, every sentence taking the reader for a zesty little ride.
Beneath the surface, the main character(s) must be caught up firmly in time, within each scene, ushered along through some unavoidable challenge.
Below that, the fundamental plot must progress compellingly, and with tight storytelling logic, from scene to scene, possessing what John Gardner called profluence — "a sequence of causally related events."
Then, there are the deeper levels of which the reader may not even be consciously aware: systems of imagery and metaphor that produce their own unfolding story, or a march of ideas that undertakes an ongoing philosophical argument about the nature of existence.
And then there's the submarine river, where the world of the book as such (aside from the fate of any given character) evolves gradually, creating its own species of curiosity and satisfaction.
Of course, I've omitted some important aspects of narrative from the above list. The point, though, is that the writer needs to manage all levels at once, generating maximum appetite in the reader, building in as many different and irresistible reasons as possible to turn the page.