“The world is dark, and light is precious.
Come closer, dear reader.
You must trust me.
I am telling you a story.”

  -THE TALE OF DESPEREAUX by Kate DiCamillo

If you are going to address your story to a “dear reader” as DiCamillo does in the quote from her award-winning children’s book above, you bring a whole new character into your story: the dear reader (which brings to mind the dear leader, North Korean dictator, Kim Jong-il.) And, as we told a recent client, this should involve some thought. Tossing in the term “dear reader” just because you want the reader to know you like him or her doesn’t really cut it. The term, after all, is a little old-fashioned and its use can be seen as pretentious, like you are trying to channel Dickens (who did, in fact, include a DR in HARD TIMES). So if you are going to summon the dear reader in the 21st century, it is best to know why and what purpose the DR is going to serve in your story.

In the example above, published in 2004, DiCamillo is deliciously creepy. She is using the DR to demonstrate her untrustworthiness. She says the reader must trust her and at the same time that she is telling a story (an untruth?) making one wonder if she really holds the reader and his welfare dear at all in her rarely-lit world.

Here are some other DRs and the role they play in stories:

The term establishes a bond between the author and reader:

Then the lesser and the greater scamp looked at each other, and for a moment or two felt a warm, sympathetic, friendly emotion for each other, and quietly shook hands.
Depend upon it there is a great deal more kindly human sympathy between two openly-confessed scamps than there is in that calm, respectable recognition that you and I, dear reader, exhibit when we happen to oppose each other with our respective virtues.
– THE STORY OF A MINE by Bret Harte

Addressing the dear reader can be an aside, a way to step outside the action and comment on it.

"Dear me!" said Mr. Hoopdriver, veering round to the new wind. "How did you find out THAT?" (the man was born in a London suburb, dear Reader.)
"I guessed," she said

– THE WHEELS OF CHANCE by H.G. Wells

The term can be used (shamelessly!) to flatter readers.

Archibald, as he had stated to McCay, was engaged to a Miss Milsom–Miss Margaret Milsom. How few men, dear reader, are engaged to girls with svelte figures, brown hair, and large blue eyes, now sparkling and vivacious, now dreamy and soulful, but always large and blue! How few, I say. You are, dear reader, and so am I, but who else? Archibald was one of the few who happened to be.
– THE MAN UPSTAIRS AND OTHER STORIES (“Archibald’s Benefit”)by P.G. Wodehouse

It can be used to add another layer of comedy onto a story. Here the writer is apologizing for a character over which he has complete control.

Dear reader, I beg your pardon for repeating such things. I know most conversations reported in books are altogether above such trivial details, but folly will come up at every table as surely as purslain and chickweed and sorrel will come up in gardens. This young fellow ought to have talked philosophy, I know perfectly well; but he didn't,–he made jokes.

– THE AUTOCRAT OF THE BREAKFAST TABLE by Oliver Wendell Holmes

The dear reader can be used as a platform for explanation.

Dear reader, there are people in the world who know no misery and woe. And they take comfort in cheerful films about twittering birds and giggling elves. There are people who know that there's always a mystery to be solved. And they take comfort in researching and writing down any important evidence. But this story is not about such people. This story is about the Baudelaires. And they are the sort of people who know that there's always something. Something to invent, something to read, something to bite, and something to do, to make a sanctuary, no matter how small. And for this reason, I am happy to say, the Baudelaires were very fortunate indeed.
-A  SERIES OF UNFORTUNATE EVENTS by Lemony Snicket