Trelawney first appears in the third book of the series, when Harry, Ron, and Hermione start divination lessons. The friends generally believe Trelawney is a fraud. However, Parvati Patil and Lavender Brown are very fond of and impressed by her. According to Professor McGonagall, her credibility as a Seer is undermined by her habit of erroneously predicting, each year, the death of one of her students, she uses it as a greeting for her class. Her more profound predictions seem only to happen when she is in a trance and unaware of what she is saying, with no memory of it afterward. However, almost all her predictions were later shown to be true in the books even if she was not in a trance.