This separation from his spellbooks had been a real problem for Harry, because his teachers at Hogwarts had given him a lot of holiday work. One of the essays, a particularly nasty one about shrinking potions, was for Harry’s least favorite teacher, Professor Snape, who would be delighted to have an excuse to give Harry detention for a month. Harry had therefore seized his chance in the first week of the holidays.
While Uncle Vernon, Aunt Petunia, and Dudley had gone out into the front garden to admire Uncle Vernon’s new company car (in very loud voices, so that the rest of the street would notice it too), Harry had crept downstairs, picked the lock on the cupboard under the stairs, grabbed some of his books, and hidden them in his bedroom. As long as he didn’t leave spots of ink on the sheets, the Dursleys need never know that he was studying magic by night.