Books can be powerful things especially when it comes to the plot.
Honestly, The Doctor probably said it better: "Books, the most powerful weapons in the world." That's the truth when it comes to several television shows.
In many cases, books and journals are both weapons and tools to fix the problem. Often the lead characters on quests, help aid them in finding peaceful solutions to their problems. Sometimes they give key insights into a character or plots.
But the books can also be the bearers of bad news, delivering the news characters don't want to here.
Let's take a moment and remember some of the times books were particularly important to a television plot.
Lucy's Journal (Timeless)
From the moment Timeless started, we knew that Lucy Preston's journal would play a significant role in the series.
During the Hindenberg explosion, Garcia Flynn presented her with a book full of her handwriting, saying it had guided him in his mission to steal the Mothership.
Lucy wrestles with the idea that her future has been all laid out for her, but the journal comes in handy in the end, giving the team a way to save Rufus during the Timeless Season 3 Episode 1, "The Miracle of Christmas."
Ellis Grey's Journals (Grey's Anatomy)
While Ellis Grey may have been a legend in her day, Alzheimer's disease meant that she wasn't up to teaching by the time her daughter Meredith arrived at Seattle-Grace to become a resident.
However, in addition to papers she published, Ellis kept several journals detailing surgeries that Meredith could refer to.
The journals proved especially useful when Maggie arrived in Grey's Anatomy Season 11 when they helped the two connect. Who knew that wine stains could be so insightful.
Last Hope Options (The Magicians)
Talk about an ominous title.
At the start of The Magicians Season 2, the Brakebills students still had to put an end to the beast. To do that, they needed a potent spell called the Rhinemann Ultra, supposedly responsible for ending World War II.
The thing was, they needed to find the book that the spell was in, and it was under an alias in the Brakebills Library.
Through lots of spells and puzzle-solving, the students were able to find the book under the name Hotel Spa Potions, and Alice was able to cast it and defeat the beast once, and for all.
The Books of Ascension (Buffy: The Vampire Slayer)
Remember that time during Buffy's senior year when the Mayor decided he wanted to ascend? Well the way Mayor Richard Wilkins got the information he needed to ascend was through The Books of Ascension.
The books don't get much screentime but are pivotal to helping the Scoobies defeat the mayor at graduation.
While she's held prisoner at City Hall, Willow Rosenberg can rip out a couple of pages to give to Giles for research. It's almost sad, because, before this, the books were in great condition.
But I guess that's the price for saving a town on a hellmouth.
Snow Falling (Jane the Virgin)
Jane's first published book, Snow Falling, was an account of her romance with her deceased husband Michael Coredero, Jr.
While she wrote the book as a form of grieving, the book ultimately proved useful when Michael turned out to be alive on Jane the Virgin Season 4 Episode 17.
Through the beginning of Jane the Virgin Season 5, Jane helped Michael try to regain his memory. It doesn't go as well as can be expected, especially since Jason is very different than Michael.
When Michael's memory does return Snow Falling does prove to be a way back into Jane's heart, at least for a time. He returns the book annotated with post-its noting everything that Jane got wrong.
River Song’s Diary (Doctor Who)
When The Doctor first met River Song, he had no idea who she was, but she was carrying a diary full of memories of him and she knew his name.
During Doctor Who Season 4 Episodes 8 and 9, the Doctor attempts to peek inside the diary, but River stops him claiming that it is his rule was that he doesn't get to see what's in the diary, ever, because the book contains spoilers for his future.
River's diary was essential throughout six seasons of Doctor Who so that the two time-travelers could place where they were in relation to each other, but it also saved the Doctor.
When Amy and Rory got married at the end of Doctor Who Season 5 Episode 13, "The Big Bang," River appears at the wedding to give Amy her blank diary.
The appearance of the blank diary prompts Amy to remember the Doctor, and he returns to the timeline and restores the writing in River's Diary.
The Book of Pythia (Battlestar Galactica)
Laura Roslin was dying of cancer before the Cylon attack on the Twelve Colonies, but the Book of Pythia gave her a way to cast herself in a new light.
The Book of Pythia was a part of the sacred scrolls, and they're both obscure and widely known in the context of Battlestar Galactica. The story that Pythia lays out is about a dying leader who will lead her people to a new land but won't live to see it.
The scrolls are very significant throughout the series, with both the humans and the Cylons being particularly interested in her writings.
While the audience never quite deciphers what Pythia means. It's stated upfront that these scrolls were never widely studied, but the fact that she gave the last of the human race faith on their journey makes it an essential book in the world of Battlestar Galactica.
Edward Spellman's Journals (Chilling Adventures of Sabrina)
At the end of Chilling Adventures of Sabrina Season 1 Episode 4, "Witch Academy," Nicholas Scratch gives Sabrina a copy of one of her dad's journals that he snuck out of the archive.
While reading the journal, Sabrina sees a picture of her mother that helps her solve an Akron configuration in which her father trapped a sleep demon that proceeded to unleash some horror on the Spellman household.
The book and the Akron configuration would also later aid Sabrina and her family in friends in finding a way to stop The Dark Lord during Chilling Adventures of Sabrina Season 1 Episode 20, "The Mephisto Waltz."
While the Akron configuration wasn't strong enough to hold him, it did give Nick the idea to use his own body to bind The Dark Lord.
Clara’s Copy of ‘101 Places to See’ (Doctor Who)
The Doctor met Clara Oswald twice before ultimately meeting her during the present timeline in Doctor Who Season 7 Episode 7.
Going through Clara's room, the Doctor found a copy of the book 101 Places to See with an inscription to Clara's mom and a pressed leaf inside of it.
On the next episode, Doctor Who Season 7 Episode 8, "The Rings of Akhaten," she brings the book with her, and on a planet that prizes things of sentimental value, the leaf kept inside of the book proves to be the key to saving the world.
Henry’s Storybook (Once Upon a Time)
Henry Mills' copy of Once Upon a Time, given to him by Mary Margaret Blanchard, is the entire reason this show starts.
Throughout Once Upon a Time Season 1, the book helps Henry identify all the residents of Storybrooke, and even helps awaken David, aka Prince Charming, from a coma.
While the book was essential to breaking the curse, the bits that weren't in it were also just as important.
The reveal of The Author and how the stories were sometimes manipulated posed interesting questions regarding the fairytales as we know them, and served as an example of how good storytelling can influence who we see as heroes and villains.
The Book of Shadows (Charmed)
The Book of Shadows on Charmed is an irreplaceable family heirloom with knowledge from an entire line of witches. It's no wonder that when demons are after them, The Halliwell Sisters consulted the book.
The thing about The Book of Shadows though, is that it's a living document, and each generation is supposed to add their knowledge to make sure the next is better equipped to fight whatever forces of evil seem to be thrown at it.
That means that as the sisters progress on their journey, the knowledge in the book has to grow.
The Book of Shadows is also pretty cool in that it seems to be sentient, unwilling to let a known demon steal it, and sometimes directing the sisters directly to the page they need.
Merlin’s Journals (Stargate: SG-1)
In a cave full of treasure, Daniel Jackson found a book.
Not just any book. Tathis was a book that would serve to give Stargate: SG-1 another two seasons as it set the team on a course to look for the Altera.
In turn, that introduced them to The Ori, also known as the show's new Big Bad.
Merlin's journals were essential to helping the team find a way to defeat the Ori. His writings led to the team to a weapon he called the Sangraal, or The Holy Grail.
The Binder (The Magicians)
On The Magicians Season 4, Julia was told to seek The Binder.
The Binder was supposed to be able to give her a way to get her powers back after she lost them re-magicking the seven keys at the end of The Magicians Season 3 Episode 13.
When she ultimately finds The Binder, she's told that it does indeed have the answers she seeks, but Julia has to think about her choice before he'll help.
Of course, all sense of choice goes out the window on The Magicians Season 4 Episode 13 when she's injured by spirit-sucked axes and Penny-23 has to make the choice of initiating her to full goddess-hood or reverting her back to being 100 percent human.
Penny chooses human.
Spencer Hasting’s Favorite Book (Pretty Little Liars)
There are some things even an identical twin cannot fake. For Spencer Hastings, that was the notes in her favorite book.
On Pretty Little Liars Season 7 Episode 20, Till DeAth Do Us PArt," A.D. was revealed to be Alex, Spencer Hasting's identical twin separated at birth.
Alex was kind of pissed that their mother gave up Alex thinking that she would live a Cinderella life that turned out to be much more cinders than a fairytale. With the death of Cece, Alex embarked on a path of revenge with an endgame to assume Spencer's life
Alex got as far as kidnapping Spencer and was getting ready to take her place when Toby noticed one mistake Alex made in trying to slip into Spencer's life.
Alex gave Toby a book of French poetry, Spencer's favorite book. During the events of the series finale, Toby looks at the book and finds that it has no annotations. Which is odd because Spencer was always writing notes in the margins.
When Spencer and Alex are seen together, Toby asks them to recite their favorite poem. Spencer is able to, but Alex hesitates. It's a real, "Will the Real Spencer Hastings Please Stand Up," moment.
At Any Cost (What/If)
Ann Montgomery had a devious and manipulative plan on What/If, but she had also published a book that revealed more about her psychology than anyone probably expected.
When Lisa decides that she needs to stop Anne from potentially stealing her company out from under her, she turns to her friend Cassidy, who begins combing through Anne's latest release for information about Lisa's investor.
Cassidy, I think I want you on my team during the apocalypse, that was a pretty smart move.
Thom E. Gemcity’s Novels (NCIS)
Special Agent Timothy McGee has been writing crime novels under a pseudonym since NCIS Season 4, but during one episode the book he was currently writing became the center of a case.
On NCIS Season 4 Episode 20, "Cover Story," a Petty Officer who McGee based a character in his book on is murdered, and the team has to use the work in progress to figure out what the killer might do next.
There was one slight problem though, McGee didn't know how this story was going to end.
Melody Malone (Doctor Who)
Doctor Who Season 7 Episode 5, "The Angels Take Manhattan," is Rory and Amy's swan song, but you can argue it was all caused by a book.
At the beginning of the episode, the Doctor is reading a book featuring a character called Melody Malone. He gets to a chapter called "The Skinny Guy" that makes him realize that the book is more than a work of fiction.
To save Rory, he pilots the TARDIS through some temporal disruptions where he encounters River Song. Much like River's diary though, they can't read the book because once you read about your future you're doomed to live it.
Amy suggests that if River wrote the book, then she must have left something non-spoilery that would make the book useful but not give away too much. She suggests peaking at the chapter titles.
When the Doctor does so, he discovers Amy and Rory's fate.
Fillory and Further Book 6 (The Magicians)
Okay, the entire Fillory and Further series are important in The Magicians, but Book 6 was especially significant and honestly: a fanboy's dream.
Jane Chatwin gives Quentin the sixth Fillory and Further book in the first act of The Magicians Season 1 Episode 1, "Unathorized Magic."
And it's this unpublished book that helps them defeat the beast.
While Quentin doesn't read the book right away, Penny does and manages to give a synopsis about what it contains, including the fact that it supposedly undoes all the Fillory books before it.
It also gives the Brakebills students vital information about Martin Chatwin and his relationship to Fillory that sets them in the right direction.
David Clarke’s Journals (Revenge)
While wrongfully convicted of treason, David Clarke had a lot of time to think and write, resulting in the show's infamous infinity box and journals.
As Emily Thorne says, the journals provided her with a road map to get her revenge on the people who destroyed their lives.
The journals also work against her, because while Emily doggedly pursues the people who wronged her and her father, Nolan Ross likes to use her father's words to ground and restrain her.
Especially when Emily is about to cross the line and kill one of the Grayson's.
Becca’s Book (The 100)
While Clarke was playing host to Josephine Lightbourne during The 100 Season 6, the answer to saving Madi from Shadeheda turned out to one of Becca's journal.
"Becca's book" as it's called gave Raven Reyes the roadmap to destroying Shadeheda in the flame, and even though it was a small part of the Season 6 plot, Madi shouldn't have been de-flamed without it.
Finding Jiya in Chinatown (Timeless)
Jiya can hold her own. When Rittenhouse kidnaps her she's about to escape, but because she's drugged, isn't able to stick the landing in The Lifeboat and ends up in Chinatown in that late 1800s.
Stranded, and unable to to get home, she has to find a way to send a message to rest of the Time Team. She finds a photographer used in a book Lucy co-authored with her mother, and the photo appears in the book.
The coordinates were essential to finding The Lifeboat, and ultimately rescuing Jiya.
The Map to Hollow Earth (Sanctuary)
In a weird dream communication, Will gets a message from Helen Magnus's father with two numbers and a symbol. The numbers correspond to gifts he's given Helen throughout her life, one being a book.
When the two objects are combined they unlock a holographic map to a city at the center of the earth.
The team spends a portion of the third season finding the way into Hollow Earth, but the map comes in handy later as well when the team faces a vampire uprising.
Rather than release a vampire army, on Sanctuary Season 3 Episode 16, Helen Magnus and Nikola Tesla trick the vampire queen into accessing the map and subsequently blowing herself and her army up.
Alison’s Copy of Lolita (Pretty Little Liars)
A copy of Vladimir Nabakov's Lolita turned out to be a key to Alison's past in the early seasons of Pretty Little Liars.
Alison based her alias off an anagram of Vladimir Nabokov's name and would spy on A while wearing a dark wig and a red coat.
The book set the liars on the trail to find out what really happened to her friend and gave them so insight into a part of Alison's life they had very little knowledge of.
What are some of your favorite books that set off a television plot? Let us know in the comments below.
Lauren Busser is a staff writer for TV Fanatic. Follow her on Twitter.