Book excerpt: Harry Potter: A History of Magic is the official book of the exhibition, a once-in-a-lifetime collaboration between Bloomsbury, J.K. Rowling and the brilliant curators of the British Library. It promises to take readers on a fascinating journey through the subjects studied at Hogwarts School of Witchcraft and Wizardry -- from Alchemy and Potions classes through to Herbology and Care of Magical Creatures. Each chapter showcases a treasure trove of artefacts from the British Library and other collections around the world, beside exclusive manuscripts, sketches and illustrations from the Harry Potter archive. There's also a specially commissioned essay for each subject area by an expert, writer or cultural commentator, inspired by the contents of the exhibition -- absorbing, insightful and unexpected contributions from Steve Backshall, the Reverend Richard Coles, Owen Davies, Julia Eccleshare, Roger Highfield, Steve Kloves, Lucy Mangan, Anna Pavord and Tim Peake, who offer a personal perspective on their magical theme.