6. Harry Potter and the Chamber of Secrets

This book is last only because it is a "self-contained" book. Meaning that although Voldemort is in the book, all of the problems that arise, are eventually solved. The diary is destroyed, Ginny is saved, the book within itself has its own resolution. We eventually learn that Harry destroyed a horcrux, but even when we figure that out it doesn't matter that much because, well, reason destroyed. This book does not really have much that makes the overall plot move forward, and for that reason, it is in 6th place.

5. Harry Potter and the Sorcerer’s Stone

Harry Potter and the Sorcerer's Stone is important because it lays the groundwork for the other books in the series. We learn that Voldemort not only killed Harry's parents, but reasonhad a reason why he did it, even though Dumbledore doesn't exactly say why. We also learn that for whatever reason Harry is a marked man. It is also the book where Harry is not yet afraid of Voldemort, which gives him the courage to say his name. We learn that Voldemort has powers we do not understand, and although he may be gone, he is not dead.

4. Harry Potter and the Prisoner of Azkaban

This book, which happens to be my favorite, is fourth on the list only because it is one of the only books where Voldemort is never actually present. It made it this high on the list because of its important background information that we learn not about Voldemort or the Death Eaters, but Harry's family and friends. In this book, we learn not only that Sirius is Harry's Godfather, but also that it was Peter who betrayed his parents. We also learn more about Harry's father and the friendships he made in school. We learn in this book just how deeply Voldemort's actions affected Harry and everyone around him. Voldemort didn't just kill Lily and James, he sent Sirius to jail and Peter into hiding and destroyed a lifelong bond these four friends had.

3. Harry and the Order of the Phoenix

Harry and the Order of the Phoenix, the longest and slowest moving by far, still has one saving grace, the prophecy. Not only do we learn about the prophecy that dictated Harry's fate, but we also learn about Harry and Voldemort's odd connection that allows Voldemort to see into Harry's mind. This connection we come to learn is more than just a result of Voldemort's killing curse 14 years ago, it is, in fact, the beginning of Harry realizing he is a Horcrux. This book also shows the ruthlessness of the death eaters and gives Harry the push he needs to fight back after they murder Sirius Black.

2. Harry Potter and the Half-Blood Prince

Although we can all agree that this may be one may not be one of the more exciting reads in the series, it is true that this book contains some of the most important information regarding Harry and Voldemort. Dumbledore and Harry going through the memories leading up to the discovery of Slughorn's memory give the information Harry needs to destroy the Horcruxes. This is crucial because Harry eventually needs to kill Voldemort.

1. Harry Potter and the Goblet of Fire

Harry Potter and the Goblet of Fire wins the title of most important to the series mostly because it is the book where Voldemort returns. The first three books may offer important background to the situation that Harry has found himself in, but none come to a head quite like Harry being faced with his mortal enemy. Once Voldemort comes back to life, the seriousness of the books takes a turn. Just as quickly as he came back, Voldemort disappeared again, which make the books after Goblet of Fire just a little less significant.