John Wilson explores the art of book cover design and meets artist Suzanne Dean, who has been responsible for more Booker-winning covers than any other designer. Writers Ian McEwan, Tom McCarthy and Audrey Niffenegger discuss the art that represents their words and Telegraph books editor Gaby Wood provides a reader's perspective on what makes a book stand out in a bookshop. As more of us than ever read books on e-readers, is beautiful design the key to the survival of the physical book?