To keep it simple and basic: Jack Finney's Invasion of The Body Snatchers succeeds first and foremost because it's a great story.
If there was nothing else to be said about it, just that it's a great story, that should be more than enough to keep it on the bookshelves for the next generation to enjoy as much as the last.
However, as with most of Finney's work, it's not just the story that makes Invasion of The Body Snatchers timeless, it's also the storyteller.
Reading Finney is like sitting out on the front porch, watching the neighbors come and go, and talking about how your day went.
There's a hominess, an honesty, that lends credibility to every word.
Add his sense of humor and obvious intelligence to the mix and you'll follow him into the strangest, most bizarre events without question.
Critics have called Invasion of The Body Snatchers an allegory for everything from the McCarthy hearings to the Cold War.
It was published in 1954, a time when such connections were easy to make.
However, in correspondence with Stephen King, Finney said, "I have read explanations of the 'meaning' of this story, which amuse me, because there is no meaning at all; it was just a story meant to entertain, and with no more meaning than that.
" But it is a story with a strong underlying truth.
That truth is this: no matter how well you know a person, you never really know him.
Is there anything more frightening?