I can remember with startling accuracy what I was doing exactly seven years ago.

That speaks not to my remarkable memory, but to the fact that Harry Potter and the Deathly Hallows—the seventh and final book in J.K. Rowling's fantastical series—was released at midnight on July 21, 2007. Like any moment that marks a transition from childhood to adulthood, there's an immediacy to my memory of that night. On the evening of July 20th my mom, my sister, my aunt, and my three cousins piled into a car and headed to our local Barnes & Noble. My eldest cousin and I both had driver's licenses so I'm not sure why our moms came with us. I suppose at that point it was just habit. We'd attended midnight releases of the past three books as a group and who were we to mess with tradition? Or perhaps subconsciously we wanted seven of us there. After all seven is the most important number in the Potter series.

Seven books, seven Weasley children (Harry's surrogate family in the wizarding world), seven players on a Quidditch team (Harry's magical sport of choice), seven Horcruxes (evil talismans that baddie Voldemort uses to earn immortality). While most retrospectives wait for a 10-year anniversary, it seems appropriate to toast the final installment of the Harry Potter series—released on the seventh month of 2007—on its seven-year anniversary.

With the current popularity of young-adult literature it's hard to remember just how groundbreaking Harry Potter was. Rowling clearly drew inspiration from everything from Lord of the Rings to Roald Dahl, but she eclipsed her predecessors in unprecedented numbers. With roughly 450 million copies sold, Harry Potter is the best-selling book series in history. Deathly Hallows remains the fastest-selling book in history. Mine was one of 11 million copies that flew off shelves on the first day alone. Rowling didn't create the YA genre, but her success went a long way to popularizing and legitimizing it. Tired of seeing the series dominate its best-seller list, The New York Times created a separate children's literature list in 2000. When Potter commandeered that as well, the Times created another list—this time for children's literature series. Since their creation, these lists have remained full of Potter's blockbuster successors like Twilight, The Hunger Games, and Divergent.

Unlike the series it influenced, however, Harry Potter is part of a rare subset of entertainment that defines a generation. It shares that honor with the likes of the Beatles in the 1960s, Star Wars in the late 1970s, and John Hughes films in the 1980s. Of course this generational ubiquity is in many ways a nostalgic construct. Not every teen went crazy for the Beatles, nor did every movie fan embrace Hughes' style. Yet from 1998-2007 it really did feel like every person my age was reading Harry Potter. It's worth noting that for all of the panic over cynical Millennials and our reliance on technology, we were also a generation that fell madly in love with a book series about love conquering hate.

I grew up alongside Harry Potter and his friends. I was nine when the first book debuted in the U.S. in 1998 but, like Harry, I discovered the magical world sometime around my 11th birthday. As I lapped up the rest of the series in the following years, the Gryffindor common room and the Burrow became palpable places in my imagination. Words like "niffler," "Nimbus 2000," and "Norwegian Ridgeback" slipped seamlessly into my vocabulary. The volumes sat patiently on my bookshelf between rereads as I attended fifth grade ice cream socials then middle school dances and later high school study sessions. My copies of the first four books are especially well-loved; their covers are frayed, bent, and grass stained. I used to claim I'd read the first book 25 times although I honestly can't remember if that was an accurate count or a boastful exaggeration. By the time Harry started his seventh and final journey in Harry Potter and the Deathly Hallows I was preparing to enter my final year of high school. When I got my hands on the last book I had been reading about Potter, Peeves, and Privet Drive for—appropriately enough—seven years of my life.

Of course Harry Potter fans came in all ages and plenty of adults fell in love with the series too. But without the rabid obsession of younger fans, the books wouldn't have become a cultural phenomenon. It's also worth noting that a majority of those ardent supporters were young women. Teen girls are often ridiculed for their preferences, but here their literary tastemaking is curiously glossed over in the narrative of the series' success. It's not the first time gender politics played a tricky role in Harry Potter. Joanne "Jo" Rowling was told to list her name as J.K. Rowling on the book's cover lest her gender scare away male readers. There's much to parse in the fact that a series written by a woman, beloved by young women, and centered on a young man has become a defining piece of 21st century literature. If Rowling's work is rightly described as inspiring a whole new generation of readers, then young girls deserve the credit for popularizing it in the first place.

It's difficult to say exactly what alchemy led to Harry Potter's extraordinary level of success (although plenty of publishers have been asking themselves that question daily for seven plus years). At least part of it comes down to Rowling's unique balance of whimsy, world building, and character development. In addition to the teen angst of the central trio, Rowling wrote a multi-generational epic with characters who felt like protagonists in their own stories, not supporting players in someone else's. As Harry's conventional hero's journey took center stage, Albus Dumbledore quietly became one of the most complex heroes in fiction. The slow reveal of his tortured past added layers to his wise persona, and Rowling trusted her young readers to make up their own minds on whether his actions were justifiable or immoral. Indeed, she often crafted characters relatable in both their strengths and weaknesses. As a bookish, bushy-haired brunette myself, Hermione Granger was an inspiration. I connected not only to her love of learning, but also to her desire to help others (which occasionally bordered on controlling them) and her inability to express her emotions. As she grew from a bossy 11-year-old to a more confident 17-year-old, so did I.

It's not an exaggeration to say that Potter has impacted almost every major friendship in my life. My sister and I would waste weekends trying out Butterbeer recipes (all of which were terrible), my high school drama class bonded over Potter Puppet Pals, and my best friend and I spent hours listing spells, long after we were too old to do so. But it's perhaps in college that the series impacted my relationships most. In an unfamiliar environment, "Harry Potter" became a sort of code word to test out new friendships. Some shrugged halfheartedly when the series was mentioned, but others perked up—eager to discuss Patronuses and plotholes (just what were the spectators watching in the second and third Triwizard Tournament tasks?). To those people I felt an instant connection. Despite coming from different places in the country, we were united by Harry Potter. We could recount almost identical stories of staying up through the night to finish books and crying over heart-wrenching moments. My one or two uninitiated friends are used to being chastised by peers for their lack of Potter knowledge.

In general, fans who grew up with the books feel great ownership over the series. Devotees are encouraged to identify with one of the four Hogwarts houses: brave Gryffindor, loyal Hufflepuff, cunning Slytherin, or wise Ravenclaw. Those somewhat simplistic divisions have proved a surprisingly useful tool for understanding motivations and priorities. If the books create a simplistic dichotomy between the "good" Gryffindors and the "bad" Slytherins, fans took it upon themselves to deepen the understanding of the house system, placing personal stake in their house identities. Hundreds of blog posts describe how a Gryffindor can be brave but foolhardy, just as a Slytherin can be ambitious but loyal. The biggest Harry Potter fan I know calls any moment of cunning success (like defending an empty seat next to you on the bus) a "Slyther-win," which never fails to make me laugh. As with any personality test, the value in "sorting" is in the self-reflection it offers. I wasn't sure why I felt so lost in my first two years out of college but remembering my Ravenclaw pride helped me realize I was sorely missing academics. I'm much happier now that I'm aware of my need for intellectual nourishment.

Potter wasn't the first series to inspire a rabid following (Trekkies had been holding fan conventions for decades by that point), but it was the first major fandom formed in the age of the Internet. In addition to dressing up and hanging out at conventions, fans could connect in huge numbers online. Popular sites like Mugglenet and The Leaky Cauldron posted art, fanfiction, and daily news while podcasts like Mugglecast and Pottercast devoted hundreds of episodes to analyzing the series. Around 2005 news that Middlebury College had introduced Quidditch as a club sport quickly spread across the Internet. Today there are over 150 teams that regularly play against one another in the official US Quidditch league. A whole new genre of music called Wizard Rock, or "Wrock," celebrated the series through songs. I have fond memories of getting lost on summer road trips and arriving at a faraway library just in time to hear The Whomping Willows sing about Draco Malfoy and Harry Potter's secret love affair. These fan creations are both unabashedly nerdy and wonderfully self-aware. In real-life Quidditch players run around the field with broomsticks in hand. Instead of chasing an enchanted ball called the Snitch, Seekers chase a fellow player dressed in gold who is allowed to run off the field and hide. In the song "Save Ginny Weasley" Harry and the Potters—the original Wrock band—ask "Are you petrified of being petrified?" before diving into the song's rocking chorus: "We've got to save Ginny Weasley from the Basilisk. / We've got to save the school again." It's both hilarious and rousing.

A generation who celebrated Harry Potter as a hobby is now old enough to turn those fandom-honed skills into careers. Today Hank and John Green manage a thriving online empire, but their first viral video was a song about Harry Potter and the Deathly Hallows. (Not to mention the fact that Potter's legitimatizing of the YA market likely helped pave the way for the success of John Green's own YA novel, The Fault In Our Stars.) A hilarious Harry Potter parody musical produced at University of Michigan went viral on YouTube and the creators quickly earned their own enthusiastic mini-fandom. Named Team StarKid, the group now runs a theater company in Chicago. Their former cast member Darren Criss—who played Harry in the production—is currently a leading actor on Glee. The entertainment website Hypable was created by former Mugglenet staffers, the one time Potter-only convention LeakyCon has expanded into a multi-fandom event, and former Wizard Rockers have transitioned their music into new avenues. The Harry Potter fandom didn't end on July 21, 2007, but it did transition into something bigger—expanding its nerdy, kind-hearted passion into other places.

Future generations will undoubtedly fall in love with the Harry Potter series just as I did. But they'll never be able to replicate the experience of waiting in anticipation for the next book to be release—moving from elementary to middle school in the interim. Instead the kids of the future will be able to read Potter all at once and with a general foreknowledge of the series. I love both The Beatles and Star Wars, but I discovered the band through best-of albums long after John Lennon's assassination and first watched George Lucas' films in bits and pieces on old VHS tapes, already aware of the infamous "Luke, I am your father" reveal. That doesn't lessen my affection, but it makes my experience different than those who kept up with the Fab Four in teen magazines or stood in line to attend the opening of The Empire Strikes Back. The art lives on forever, but the zeitgeist energy is ephemeral.

After reading all night I finished Harry Potter and the Deathly Hallows around noon on July 21, finally closing the cover—literally and figuratively—on a book series that had defined my childhood.

Over the years Rowling has occasionally returned to the wizarding world in small ways. She recently released a short story, on her fansite, Pottermore, and the enthusiastic response indicates she's still able to call upon her fandom whenever she likes. That bodes well for her upcoming Harry Potter play and a spin-off film about a wizard who hunts magical creatures. I'll likely engage with these new properties as a curious fan, but without the rabid desire for material that one characterized my love of the series. But even if my zealous enthusiasm is in the past, the series has weaved tangible threads through my life. My love of critical analysis and my interest in fandoms—developed during years of speculating between books—have become cornerstones of my job as an entertainment writer.

But most importantly of all, Harry Potter has become a foundation for a lot of my friendships. If the series itself has diminished in importance, the relationships it fostered have only grown. Seven years have passed since that final book, but my place in the Potter generation continues to shape my life for the better.

As Rowling once wrote: All was well.