McGonagall invokes this a few times when she sees that Trelawney is scaring Harry with predictions about his death, to show that she thinks Divination is bunk.and readers know that things are going to get really interesting from now on. The result is that, by the end of this book, the story's landscape has irrevocably changed. It also has, quite possibly, the most complicated plot of the entire series, drawing in characters and events from all over the place the Prisoner of Azkaban is obviously important, but the way he is important zig-zags several times over the course of the novel, and the same thing happens to a lot of other characters. It also marks the point where the books started to become more serialized with each ending setting up the next one (the first two books were largely self-contained stories whose events did not significantly influence the progression of the series' overarching plot). The book's popularity may be partially due to the introductions of Sirius and Lupin, whom some fans consider to be two of the coolest characters in the series. Remus Lupin, meanwhile, makes his first appearance, taking on the dreaded Defence Against the Dark Arts post. In response, the Ministry of Magic sends Dementors, a Black Cloaked race of dreadful creatures who guard Azkaban, to guard Hogwarts and their Emotion Eating powers seem to affect Harry especially. Sirius Black has escaped from Azkaban, the wizarding prison. It is also often considered the point at which the series Grew the Beard. Published July 8, 1999, this was the last book published separately in the US and UK and the last 'quiet' release of a Harry Potter book.

Harry Potter and the Prisoner of Azkaban is the third Harry Potter book.

Sirius black prisoner of azkaban