Hermione Jean Granger is a fictional character in J. K. Rowling's Harry Potter series. She first appears in the novel Harry Potter and the Philosopher's Stone (1997), on the Hogwarts express as a first year student on her way to Hogwarts. After Harry and Ron save her from a mountain troll in the girls' restroom, she becomes best friends with them and often uses her quick wit, deft recall, and encyclopaedic knowledge to lend aid in dire situations. Rowling has stated that Hermione resembles herself as a young girl, with her insecurity and fear of failure.