A character writes a letter, every word chosen with care, full of enough heart to make a strong man weep... And drops it into a drawer, never to be seen again.
This is a message (a letter, a recording, an e-mail) to someone the sender knows will never receive it. This is often a hand-written letter, for a more personal note and since speed obviously isn't of the essence.
This can be used to present a first-person narrative in an interesting way, making it very often a sub-trope of Surrogate Soliloquy. For Bonus Poignancy Points, the would-be recipient is often dead, in which case this is a sub-trope of Talking to the Dead. In-universe, it can be used to collect one's thoughts by using an imaginary sounding board, a way to cheat Never Got to Say Goodbye (take that, Death!), or it can be used if you really, really need to say something, and there's no one (alive) to say it to.
It is certainly not unknown to happen in real life, of course. And, being a well-established trope, it is definitely capable of being subverted.
If this is a message that was never intended to be sent, but is sent anyway, and there is a (presumably non-dead) recipient for it, this becomes an Irrevocable Message.
On TV or in a movie, expect a Voiceover Letter.
Not the case of the sender expecting to be dead by the time the message is received (which is nearer Dead Man Writing). Also not the case in which a message is written to be sent, but ends up not sent for one reason or another.
- Yu-Gi-Oh!: Bakura is seen writing a letter to his late sister.
- Kurau Phantom Memory: After Kurau receives her powers in the lab accident, her father's Mad Scientist boss keeps subjecting her to tests For Science, without regard for her safety or comfort until her father has her smuggled out of the facility to be raised by foster parents. Despite his command that she must cut off all contact with him, she is shown writing letters to him as she grows up. The last scene of this montage shows her releasing her latest letter to fly away in the wind out to sea...
- Fairy Tail: One chapter reveals that Lucy has been writing letters to her deceased mother about her adventures with the True Companions. She stored them in a small drawer in her house.
- In 5 Centimeters per Second, Takaki often writes emails for his childhood love Araki but never sends them.
- Spider-Man: Blue has a tape recorder variant. Peter records a message to the deceased Gwen Stacy, reflecting on his time with her and explaining she's the reason he's always a bit blue around Valentine's Day. When his wife Mary Jane hears him, rather than be upset that he's talking to his lost love, she understands and asks him to say hello for her.
- Gen¹³: At least one story (written by Adam Warren) had Caitlin Fairchild 'narrate' the events of the issue after the fact through writing an e-mail to her recently-deceased father. The final panel of the story is her hitting the 'Delete' button once she's done.
- Batman #480 "To the Father I Never Knew" is titled after a heartbreaking letter Tim Drake wrote to his father describing just how little they knew each other due to the fact that Jack had essentially abandoned him for the first fourteen years of his life, a confession that Tim was now Robin and his wishes that they could start over even though he knows they can't. His father never saw it as Tim never truly intended to give it to him.
- The G.I. Joe fanfic A Ninja Commando's Christmas Letter is Snake Eyes being coerced into writing his dead family as therapy.
- The My Little Pony: Friendship Is Magic fanfic Twilight's Final ends with a friendship report, much like many of the episodes do. It's left on Celestia's grave.
- Of Mares and Magic: When Trixie goes Wandering the Earth near the end of the story, she writes many letters about her adventures, the majority of which cannot be delivered because she's too far away from Equestria. They also reveal her private feelings for Twilight Sparkle, which she wants to keep secret.
- In Teaching the Professor to Love Again after Harry discovers that he's actually Snape's son he writes a letter to James Potter about his feelings on the matter.
- In Forrest Gump, Forrest Jr. writes a letter to Jenny after she dies. Forrest leaves it at her grave.
- In The Clockwork Angel, while Tessa is imprisoned by the Dark Sisters, she writes letters to Nate for comfort, knowing she most likely would not be able to send them.
- Like a Bone in the Throat by Lawrence Block: A condemned murderer writes a letter to his victim's brother gloating about how much he enjoyed the crime in excruciating detail—then keeps it aside as he mails a much more repentant letter as part of a scheme to reduce his sentence. It works, because the brother wants him released to kill him personally, but that's not quite the end of the story.
- Dear Mr. Henshaw by Beverly Cleary: He's not dead, but the second half is a diary rather than letters to Mr. Henshaw. Leigh keeps beginning the entries "Dear Mr. Pretend Henshaw" because he's used to it and it makes it easier for him to write.
- The Diamond Chariot: In the end of part 1, the captured spy writes a letter to his long-lost-but-recently-found father, then burns it and commits suicide.
- Magnum, P.I.: The title character writes a letter to the daughter he thinks is dead, in a plot about why he doesn't kill her murderer.
- M*A*S*H: In the episode "Dear Sigmund", Sidney Freedman feels down in the dumps after a psychiatrist patient of his commits suicide because of voices in his head. Wanting a "vacation", Sidney retreats to the 4077th for a couple of weeks; while there, he writes a letter about the people and the hijinx of the 4077th to none other than Sigmund Freud. B.J. even remarks,
B.J.: Sidney... you're a psychiatrist, don't you think writing a letter to Sigmund Freud is a little crazy?Sidney: Who better than he would understand?
- Smallville: In one episode, Chloe writes a letter to Clark telling him how much she loves him, never planning to send it. Several seasons later, after Chloe has hooked up with Jimmy Olsen, Clark happens to find the letter.
- The Suite Life of Zack & Cody: Maddie writes an insulting email to Mr. Moseby to vent her frustrations about his treatment of her. London sends it, and the group tries to break into Mr. Moseby's office to delete it before he reads it. They delete the email, but Mr. Moseby has already read it on his smartphone.
- Deep Space Nine. "In The Pale Moonlight" has a Framing Device of Sisko dictating into his personal log how he secretly incited a war between the Romulans and the Dominion. At the end of the episode, Sisko erases the log as he obviously can't risk anyone finding out about it; the whole episode was just Sisko wrestling with his conscience.
- Played with in the Star Trek: Voyager episode "Thirty Days", which has a Framing Device of Tom Paris dictating How We Got Here in a message to his estranged father who's on the far side of the galaxy. Tom tells his friend Harry Kim that he's going to erase the message, but in the end he saves it to Voyager's computer with instructions to transmit it to his father if they ever make it home.
- "The Ghost of Bobby Smallwood" from Resident Alien reveals that Asta Twelvetrees has written one letter to her biological daughter Jay on each of her birthdays going up to her 18th written in the episode, which she keeps in a box, never sent.
- "Big Lie, Small World" by Sting is about a man who accidentally posts such a letter, then goes to increasingly insane lengths (to the point of holding the postman at gunpoint) to intercept it.
- The Vocaloid song A Clingy Boy Sticking for 15 Years has an ending that reveals that the girl the singer has been writing letters to for 15 years had been Dead All Along. Quite a Mood Whiplash compared to the goofy lyrics of the rest of the song...
- Promethean: The Created's second edition manual features a letter written to a certain "Ysolde", thanking her for granting life to the one who wrote the letter. Despite the grateful tone of it, the letter repeatedly states that they will never meet again, and considering the average Promethean's way of life, it's likely she will never receive the letter, and that it was meant mostly as catharsis for its author.
- Harvest Moon: A Wonderful Life: The framing device is the player's mentor figure/farm hand writing a letter to the player's deceased father about the farm's progress, the player's growing family, and how much has changed over time.
- In Kingdom Hearts III, Kairi writes letters to Sora that she never intends to send to him. When Axel points out that Merlin would send them for her, she replies that she writes them more for herself then she does for him.
- In Life Is Strange: Before the Storm, Chloe writes unsent letters to her best friend Max who moved to Seatle years ago. At the end of the game, Chloe decides to stop because she feels like she has to move on and live in the present with Rachel.
- Family Guy parodies this in one episode. A family therapist tells the Griffins to write angry letters addressed to the other family members, but not send them. Naturally, Peter missed that last part of the instructions.
- The creator of Hey Arnold! proposed a Spin-Off called The Patakis, which would have centered on a teenage Helga after Arnold, her boyfriend of several years, moved away. Had it been made, Word Of God says that each episode would have featured her writing him a letter and then saving it in a binder rather than mailing it.
- The Looney Tunes Show: In "You've Got Hate Mail", Tina teaches Daffy to type up e-mails and not send them as a stress exercise. Unfortunately, Daffy accidentally sends insulting e-mails to practically everyone he knows.
- In Littlest Pet Shop (2012), Blythe writes up an over-the-top mushy love letter to her crush in an attempt to vent her feelings. She then throws it away, but misses the trash can. When her father passes her room later, he sees the envelope sitting on the floor and assumes that Blythe, being a teenager and unfamiliar with things like "snail mail," didn't realize she had to actually mail a letter for it to reach its recipient, so he "helpfully" takes care of that for her.
- Abraham Lincoln once advised a friend to write a vitriolic letter to an enemy, and then not send it, to get the anger out without making things worse.
- Franz Kafka wrote a letter to his father, which ended up being so long that it spanned 103 handwritten pages... only to never actually have it given to him.
- Richard Feynman, noted physicist (How noted? He has a page here), wrote a love letter to his wife 16 months after she died. It remained sealed until after his death, making it perhaps a rare real-life case of both this and Dead Man Writing.
- Isaac Asimov described a variation on Lincoln's advice. When sufficiently provoked, he would write an angry letter, prepare it for mailing, and then tear it up (making sure to destroy the stamp in the process).