Most definitions of 'premise' seemed to use the word premise to explain premise (???).
Let's start with what premise is not. It is not theme. Theme is more than a singular words, like LOVE or WAR. If I said the theme of my novel Dog Show Detective is IDENTITY, you would be right to ask 'what about it?' If I said 'Identity is based on perception' or 'Identity can be misleading', then I would be getting closer to relaying my theme.
What about premise?
Premise is more specific than theme. It tells the reader/potential publisher/anyone who will listen, exactly what your story is about. Premise is the basis of your story.
I found a great blog that covered Premise at: Screenwriting Tips for Authors
Alexandra Sokoloff said: "That sentence really should give you a sense of the entire story: the character of the protagonist, the character of the antagonist, the conflict, the setting, the tone, the genre. And - it should make whoever hears it want to read the book."
Based on Alexandra's explanation, my premise for Dog Show Detective would be:
Kitty Walker is a shy 11yr. old, she thinks entering her Miniature Schnauzer in shows will impress her busy mother, but she could never imagine she would find a valuable missing dog, which the owner claims is an impostor, or that someone is trying to keep the dog's identity a secret at any cost, even murder.
In Holly Lisle's course on writing a novel, How To Think Sideways, this is called the 'Sentence'. Holly goes on to use the sentence in How To Revise Your Novel, (one of my favourites courses), where every scene is given its own sentence. This technique has made revising much easier for me. For example, one scene-sentence from my novel is:
The Walkers tend to the mess left by the intruder and wonder why nothing is stolen until Kitty realises Hitchcock [the mystery dog] is missing.
I'd be happy to leave my premise as these examples. But there is another step. James Frey in How to Write a Damn Good Novel explains premise as a "statement of what happens to the characters as result of the core conflict of the story". He goes on to say you then take the elements and break it down into a message that is proved by your story.
For example, a Winnie the Pooh animation I saw with my kids would have had 'the sentence' of:
Pooh and his friends must go on a dangerous adventure to find their beloved Christopher Robin, they each doubt their ability to succeed, but must prove themselves wrong.
You are braver than you believe, stronger than you seem and smarter than you think.
Ok, I stole that line from Pooh quotes. Perhaps it could be: You can surprise yourself with what you can achieve if someone you love needs your help.
'You are braver than you believe...'
Another take on Premise comes from Sandra Scofield in her audiobook course, Writing from Premise (available in iTunes), with the suggestion that Premise must be when one element or action in your story LEADS TO a set conclusion (which could be positive or negative). One example given is: Unconventional love leads to new life. This was a premise given for a story about a woman who falls in love with a younger man despite her misgivings and enjoys the journey.
Taking this advice, my premise for Dog Show Detective could be: Making assumptions leads to being deceived. And, I probably have a premise of: Believing in yourself leads to surprising achievements.
Many experts have implied a lack of premise leads to failure in a novel (oooh, that's a premise!), but I believe if you have a 1st draft of a story, you can always revise your novel with a premise. Once you have your premise, make sure every scene moves towards either proving your premise correct, or being the exception to the rule (one character's subplot might act as a binary to the premise). If you find a scene that has no relation to the premise, perhaps it needs to be cut?
Remember: Having a premise leads to a 'damn good' novel!