Hogwarts: An Incomplete and Unreliable Guide, Page 5

  reason for their failure was simple: none of them was a Parselmouth.

  So there you have it: it’s not a guided tour, nor is it entirely complete, but you’re now privy to some of the famous wizarding school’s many secrets. We leave you with these small pieces of advice: tread carefully when using a Time-Turner, stop searching for the Chamber of Secrets – unless you’re a Parselmouth – and don’t linger too long before the Mirror of Erised.