Author J.K. Rowling was in the middle of writing Harry Potter and the Chamber of Secrets when the first Harry Potter novel (Harry Potter and the Philosopher's/Sorcerer's Stone) came out in Britain in 1997. Following the runaway success of the first Harry Potter book, US publishers launched a bidding war involving six-figure dollar amounts for the rights to bring the Harry Potter novels stateside (source). Once Harry appeared on the US market in 1998, Rowling became an international celebrity. Rowling comments:
The stakes seemed to have gone up a lot, and I attracted a lot of publicity in Britain for which I was utterly unprepared. Never in my wildest imaginings had I pictured my face in the papers – particularly captioned, as they almost all were, with the words "penniless single mother." It is hard to be defined by the most difficult part of your life. (source)
So, picture for yourself a woman working in relative peace on a new book project. Then, suddenly, your world changes entirely: you're hugely famous (and rich), not only in your own country but around the world. Imagine the pressure that Rowling must have felt to make Chamber of Secrets as – or more – awesome than the first book. Rowling recalls:
At one third of the way into writing [Chamber of Secrets], [Sorcerer's] Stone had this huge success which was totally unexpected. I was happy about that, but it also frightened me because I thought I cannot reproduce this, it is a flash in the pan, I was temporarily blocked in writing Chamber of Secrets. (source)
Thankfully, J.K. Rowling's worries about sudden fame didn't stop her from finishing Chamber of Secrets. We'd regret not having this second installment in the series, filled as it is with priceless characters like Gilderoy Lockhart and young-but-still-evil Tom Riddle. The book appeared in England on July 2, 1998, and in the States on June 2, 1999, topping bestseller lists in both countries.
The current shape of Chamber of Secrets came as a surprise even to Rowling, who started out the second book under the working title Harry Potter and the Half-Blood Prince. Sound familiar? Yep, that's the sixth book – originally, she was going to include the Half-Blood Prince storyline alongside this narrative of Tom Riddle's diary. However, as she wrote, she realized she "had two major plots here that really did not work too well together side by side, so one had to be pulled out, it became clear immediately that. [She] could have soldiered on, included that information there and that would have been messed up the later plot […] the revelations about the half-blood, for instance, would have blown a lot of things open" (source).
So instead, Rowling kept Chamber of Secrets to a cool three-hundred-odd pages. The short length and relative straightforwardness of the plot keeps the tone consistent with Book 1. At the same time, Harry's first experience of teasing and exclusion at Hogwarts reminds us that, while the wizarding world may be filled with strange and wonderful things, wizards are still human beings with the same troubles that we share. Yeah, Harry's a wizard – but that's not going to solve all of his social problems. Chamber of Secrets serves as an important transitional book to the isolation and darkness of Prisoner of Azkaban, but especially Goblet of Fire and Order of the Phoenix. It introduces a slightly grimmer side to Hogwarts and to Harry, while still keeping things light for the kids who enjoyed Sorcerer's Stone.
There are scores of reasons why you should care about Harry Potter. To name one: he's been one of the most important money-making engines in the publishing industry for the last decade. As well, the Harry Potter movies have been big in the box office ever since Harry Potter and the Sorcerer's Stone came out in 2001. Beyond economics, he's one of the most beloved fictional characters ever created, coming in number two in Entertainment Weekly's list of "The Hundred Greatest Characters of the Last Twenty Years," beat only by Homer Simpson (source). Still, these are all general statements about Harry Potter as a series. Why should you care about Chamber of Secrets specifically?
Chamber of Secrets is short and sweet like Sorcerer's Stone, but it departs from the first book in that it depicts Harry's alienation from the wizarding world for the first time. Harry spends the first book falling in love with magic and with wizard society. In the second book, though, he has to deal with suspicion and rumors even at his beloved Hogwarts.
We don't know about you, but we have certainly had experiences being suspected of doing something wrong that we haven't done. It's absolutely horrible. You begin to wonder, did I do something wrong? Maybe I have been behaving badly, even if I don't think I have. If the whole world agrees that you are guilty of something, it's hard to believe that you aren't. Harry suffers precisely this self-doubt in Book 2. He begins to suspect that he is a Slytherin, even though he chose Gryffindor House. He certainly has more in common with Voldemort than is comfortable for him to admit. What if he is the Heir of Slytherin?
The trouble with remaining true to your convictions is that it is hard to have faith in yourself when no one else believes you. Even though Chamber of Secrets is a light-hearted read compared to Order of the Phoenix, Half-Blood Prince, or Deathly Hallows, it still tackles the importance of making your own choices and maintaining faith in those decisions, even when the rest of the world doesn't believe in you.
In Book 1, Harry shows his courage by facing down Voldemort, who is sticking out of the back of Professor Quirrell's head. In Book 2, though, Harry shows double that courage by continuing his search for the Chamber of Secrets, even when the whole school thinks he's a danger to himself and others, and by facing down Voldemort. Harry is a human being, so of course the rumors of his fellow second years (and the rest of the school) upset and worry him. Even so, he overcomes his self-doubt to save Ginny Weasley from Slytherin's monster. That's real courage: to feel fear and doubt, but to go on all the same.