TheHarry Potterseries remainsone of the most successful franchises of all time, thanks to a generation whose childhood was defined by the series. The series of sevennovelsbyJ. K. Rowling, plus eight films, tells the story of the titular boy wizard (Daniel Radcliffe) and his battle against the evil Lord Voldemort (Ralph Fiennes), and its popularity has led to additional books, video games and an upcomingtelevisionadaptation. The first book was published in 1997, and the book series finally came to an end a decade later, in 2007.
As is always the case with movies based on books, not everything from the source material makes it to the screen —it would be nearly impossible to include every single plot line and character introduced over the series' thousands of pages. At best, changes and omissions deprive moviegoers of the full story at best and cause confusion and lingering questions at worst.

10James and Lily’s Relationship
How did Harry’s parents fall in love?
Harry’s parents, James (Adrian Rawlins) and Lily (Geraldine Somerville), met while students in Gryffindor House at Hogwarts, but Lily disliked James at first.In their final year of school, after James had matured, they became a couple. After graduation, they got married and had a son, Harry (Radcliffe). They were killed in their home by Voldemort, who also intended to kill Harry, and the bookHarry Potter and the Deathly Hallowsrevealed they were just 21 years old at the time.
While James and Lily’s relationship and lives were addressed in the movies, the books went into more detail about how it began, from Lily’s early disdain for James to her change of heart after he evolved in their later years at school.The details about their relationship revealed in the books made it easier to understand how and why they became a couple, something which was glossed over in the movies.

Harry Potter and the Deathly Hallows - Part 1
9The Wizarding World Economy
How exactly does wizarding money work?
The money system in the Wizarding World was made up of Galleons, Sickles and Knuts, and although they were referenced in the movies,the books offered a more detailed explanation of how they worked, including what their value was and what they looked like. InHarry Potter and the Sorcerer’s Stone, when Harry first took money out of his vault at Gringotts, the Wizarding bank in Diagon Alley, Hagrid (Robbie Coltrane) explained the exchange rate of each coin.
While the way the monetary system worked wasn’t one of the most burning questions left unanswered in theHarry Potterfilms, it was still information moviegoers missed out on. Although it wasn’t crucial to the plot,it still added to the series' lore. In the books, the scene in which Harry and Hagrid visited Harry’s vault helped immerse readers in the world, as they were experiencing it for the first time, just as Harry was.

8Weasleys' Wizard Wheezes
Who funded the Weasley twins after they dropped out of Hogwarts?
After leaving Hogwarts in the aftermath of an elaborate and fitting prank, twins Fred (James Phelps) and George Weasley (Oliver Phelps) opened a joke shop called Weasleys' Wizard Wheezes inHarry Potter and the Half-Blood Prince. The shop featured everything from Muggle magic tricks to the twins' own inventions. George continued to operate the shop after Fred’s death. While the movie never addressed the shop’s origins,Harry gave the twins his winnings from the Triwizard Tournament at the end ofHarry Potter and the Goblet of Fire.
Weasleys' Wizard Wheezes was one of the best, most lighthearted parts of the series.It was a wonderful natural progression for the twins, who had a reputation for being pranksters both at home and at school. And while its source of funding wasn’t one of the biggest mysteries, it was an interesting detail. It addressed Harry’s inherited wealth and the fact that he didn’t need the money and showed his relationship with the Weasleys.

Harry Potter and the Half-Blood Prince
As Harry Potter begins his sixth year at Hogwarts, he discovers an old book marked as “the property of the Half-Blood Prince” and begins to learn more about Lord Voldemort’s dark past.
7The Two-Way Mirror
Where did the two-way mirror come from?
As Hermione (Emma Watson) was being tortured in Malfoy Manor inHarry Potter and the Deathly Hallows, the trio was rescued by Dobby (Toby Jones), who was sent by Dumbledore’s (Richard HarrisandMichael Gambon) brother, Aberforth (Ciarán Hinds), to find them.Aberforth had used half of a broken two-way mirror to keep an eye on them and find them. While the movie didn’t go into much detail, the books explained the origins of the mirror and how Aberforth came into possession of his half.
The two-way mirror was first introduced in theOrder of the Phoenixbook, when Sirius Black (Gary Oldman) gave it to Harry so they could keep in touch, but after Sirius' death, Harry destroyed it in anger. But this was not depicted in the movie—and what was an unimportant detail in one book eventually became a crucial device in another. Without its backstory, Harry using the mirror inDeathly Hallowsfelt random and too convenient.

Harry Potter and the Order of the Phoenix
With their warning about Lord Voldemort’s return scoffed at, Harry and Dumbledore are targeted by the Wizard authorities as an authoritarian bureaucrat slowly seizes power at Hogwarts.
6Barty Crouch Jr.’s Escape From Azkaban
How did he trick the Dementors?
Barty Crouch Jr. (David Tennant) was a devoted follower and trusted Death Eater of Voldemort’s who was sentenced to Azkaban and escaped. He then used Polyjuice Potion to pose as Alastor Moody (Brendan Gleeson) at Hogwarts for an entire year inGoblet of Fire. When he was discovered, Dumbledore (Gambon) made sure to alert Azkaban that they were missing a prisoner, butthe books explained his dying mother used Polyjuice Potion to take his place.
Escaping Azkaban was nearly unheard of in the Wizarding World, and when it happened, it was major news—news of Sirius Black’s escape inHarry Potter and the Prisoner of Azkabanwas everywhere, and everyone knew about it. Barty’s escape, however, went largely unnoticed, and because it was barely addressed in the movie,it’s understandable that fans would want an explanation for how he managed it. The books also went into detail about how his father kept him hidden.
Harry Potter and the Goblet of Fire
The fourth movie in the Harry Potter franchise sees Harry (Daniel Radcliffe) returning for his fourth year at Hogwarts School of Witchcraft and Wizardry, along with his friends, Ron (Rupert Grint) and Hermione (Emma Watson). There is an upcoming tournament between the three major schools of magic, with one participant selected from each school by the Goblet of Fire. When Harry’s name is drawn, even though he is not eligible and is a fourth player, he must compete in the dangerous contest.
5Rita Skeeter’s Gossip Intel
How did she get her information?
When the Triwizard Tournament began inHarry Potter and the Goblet of Fire, the press descended upon Hogwarts to cover it, including Rita Skeeter (Miranda Richardson), a gossip columnist for the newspaper the Daily Prophet. The book revealed she was an unregistered Animagus—Rita used her ability to transform into a beetle to get access to places she otherwise couldn’t, leading to scoops on stories no other reporters could get.
In the movies, Rita Skeeter appeared to be a particularly skilled and ruthless reporter who was willing to go to great lengths for a story, and they never explained just how she got one major scoop after another—but the books did.The details made her character and the plot more interesting, while also making her come off even worse than she did in the movies. She certainly seemed to be Rowling’s way of criticizing the press.
4The Attack at the Café
How were the Death Eaters able to find the trio?
After Bill (Domhnall Gleeson) and Fleur’s (Clémence Poésy) wedding was disrupted by Death Eaters inHarry Potter and the Deathly Hallows, Harry, Ron (Rupert Grint), and Hermione fled to a café on Tottenham Court Road to decide what to do next, where they were quickly found by more Death Eaters. In the book, Ron explained that because few people were brave enough to say Voldemort’s name, a taboo was put on it,leading Death Eaters to the trio after one of them spoke his name.
In the book, Ron explained that because few people were brave enough to say Voldemort’s name, a taboo was put on it…
As the situation became more dangerous for Harry, things also became more chaotic, and certain details in the series were glossed over. This included exactly how Death Eaters were able to find the trio in the café.The taboo wasn’t mentioned in the movie, making the way the trio was found unclear—but it could’ve been explained easily. Still, some observant viewers correctly suspected that saying Voldemort’s name had something to do with how they were found.
3Lord Voldemort and His Horcruxes
How did Voldemort decide what he’d turn into Horcruxes?
Harry Potter and the Half-Blood Princerevealed Voldemort (Fiennes) made seven Horcruxes,objects which each stored part of his soul and therefore made it impossible for him to be killedif they weren’t destroyed first. A person had to be killedfor a Horcrux to be made, andVoldemort made a total of six—plus Harry inadvertently also served as a Horcrux of sorts. Harry sets out to destroy them all before facing Voldemort.
In the series, Horcruxes were considered to be one of the worst forms of dark magic. They were an important part of not just the plot of the series but Voldemort’s character, andthe movies left out a lot of information about what they were and how they were created, including who he killed to make them. Voldemort chose objects which were important to him, and their stories added depth to his character.
2The Boy Who Lived
How did Harry survive the Killing Curse?
Harry’s battle against Voldemort inHarry Potter and the Deathly Hallowsculminated in Voldemort using the Killing Curse against him—but surprisingly, Harry survived. The book offers a few explanations for this. First, because Harry himself was a Horcrux,the Killing Curse actually destroyed part of Voldemort himself. Second, Harry possessed the Elder Wand. And finally, he survived the curse as a baby thanks to the protection of his mother’s love, which followed him throughout his life.
While Harry and Voldemort’s final duel was adapted from the books quite well, the movie left out some details crucial to explaining just how Harry survived—without that explanation, Harry’s survival was confusing and too convenient, even though he’d already survived the curse as a baby. Most notably,Harry’s survival thanks to his mother’s protection reinforced the series' theme of the power of love, bringing Harry’s story and his conflict with Voldemort full circle.
Harry Potter and the Deathly Hallows - Part 2
Harry, Ron, and Hermione search for Voldemort’s remaining Horcruxes in their effort to destroy the Dark Lord as the final battle rages on at Hogwarts.
1The Identity of the Marauders
Who are Moony, Wormtail, Padfoot, and Prongs?
InHarry Potter and the Prisoner of Azkaban, Fred and George give Harry the Marauders' Map,an enchanted map of Hogwarts which showed where all of its inhabitants were at any given moment. It was created by the Marauders, a group of four friends—Remus Lupin (David Thewlis), Peter Pettigrew (Timothy Spall), Sirius Black, and James Potter, also known as Moony, Wormtail, Padfoot and Prongs, respectively. And while their identities are clear in the books, they’re never actually revealed in the movies.
Without knowing who the Marauders actually were, people who watched the movies but didn’t read the books were left with some pretty big questions. While not every plot point or detail from the books could fit into the movies,the backstory of the Marauderswas not only interesting but importantand beloved by fans, andPrisoner of Azkabansuffered as a result of its exclusion—and it could’ve been addressed fairly quickly and easily.
Harry Potter and the Prisoner of Azkaban
Harry Potter, Ron Weasley, and Hermione Granger return to Hogwarts School of Witchcraft and Wizardry for their third year of study, where they delve into the mystery surrounding an escaped prisoner, Sirius Black, who poses a dangerous threat to the young wizard.