Recently, I came across a comment that indicated foreshadowing was a lazy way of creating backstory, and I so disagreed with the sentiment, I had to go trawling the net to see what I could find.
By definition foreshadow means - To present an indication or a suggestion of beforehand; presage.
If you take that comment literally, I suppose you could almost agree with the initial comment, but if it is used, as most writers do, to add tension, suspense and depth to a story, then dumping a load of backstory defies the original charge. Instead of adding curiosity and engaing the reader's interest, it is more likey to bore them sufficiently and encourage them to sling the book across the room.
Foreshadowing is a skillful art of dropping hints of events and actions to come. They may come in a few pages, or the reader may be well into the story when he/she get's that 'ah-ha' connection of the dropped clue in chapter one or two.
Foreshadowing can be so subtle the reader is lead in the direction the author want's them to go without feeling cheated at the end of the book, or it can be sledge-hammer blatant and like a road sign indicates the destination, but it is how the author reaches the destination that will hold the reader's attention until the final page.
In the literary sense, foreshadowing is a technique used to heighten suspense, add depth, and engage the reader through curiosity by dropping hints.
On Writing.com Suze the Rock Chic uses Conan Doyle's Hound of the Baskerville to illustrate the skifull use of foreshadowing. As she says, the story is packed full of foreshadowing, and you could be forgiving for thinnking that with the use of so much foreshadowing how on earth did Conan Doyle manage to fill the pages with so much suspense?
Doyle maximised the use of the tool and used every variant of it. Dialogue, flashbacks, action and description, and it is all set out on a board of great preperation.
You can use foreshadowing to set up a believable narrative. In other words, it prepares the reader for upcoming events or actions. Like most writing tools, it is how they are used that pursuades readers to come back for more.
Foreshadowing is a powerful tool all writers should become familiar with.