Most writers would agree the beginning of a story is the most important part. That's where the reader gets "hooked" and continues read on or abandons the book.
In Les Edgerton's book, he describes in broad strokes, fine strokes and with examples how to achieve what his subtitle proclaims.
According to Edgerton, you can't write the opening until you know in significant detail who your protagonist is and what the story is about. To do this you must first identify your hero or heroine's "storyworthy problem", that would be the problem that is just below the surface and is gradually revealed as the story unfolds.
From that discovery, and Edgerton urges you to drill deep to find out what's really bugging your protagonist, comes the inciting incident. This is where the story begins, the moment where the status quo is upset and the protagonist sets about to resolve it.
The inciting incident presents the first indications of the bigger issue, the storyworthy problem.
Don't start with backstory - bringing the reader up to date on your protagonist's life, start with "trouble" - an incident presented in an action filled scene that incites your protagonist and reader to carry on to resolution.
A provocative opening sentence, an exciting inciting incident giving a glimpse at the storyworthy problem and you're on your way.
Complicated? Maybe, but Edgerton hammers it home again and again (with examples).
Hooked may very well be the most important book you'll read about writing. Edgerton writes in non-academic, easy to understand language, includes entertaining examples and even gives agents and editors the last word on the most common mistakes made in the manuscripts they see and, you guessed it, a bad beginning ranks right up there.
Edgerton's prescription on how to come up with a good story opening is actually more than that, a lot more. It's the formula for a sound story structure.