This book is wondrous spellbinder with lot of new characters added. After spending half summer at Dursleys, Harry lives their housemaking despicable sister of uncle vernon float in the night sky. He meets minister of magic at Diagon alley and also his friends Hermoine and Ron with his family. Then they go back to Hogwarts to start their third year. Once again there is new defense against dark art teacher - Professor Lupin, which turns out to be old friend of harry’s father James Potter. He also gets to know the Sirius black who was in Azkaban for betraying his father but was innocent. Lupin teaches him the Petronous charm to fight against Soul-sucking dementors, which are hovering over school. Harry gets to know lot about his father and his adventures - feels amused. This book gives friendship a new meaning and tells you should not betray your friends. This book soars with laughs, thrills and kind of breathless surprise only found in a Harry Potter adventure books.