Siddhartha Mukherjee's "biography" of cancer, The Emperor of All Maladies, has won the Guardian First Book award. The book has already been awarded a Pulitzer prize for general non-fiction. Mukherjee, an American oncologist, spent years writing the book - often on the bus to and from work. Its expansive narrative covers the history of the disease, how cancer remained a societal taboo well into the 20th century and our attitudes towards it today. Throughout Mukherjee includes moving stories and case studies of his patients.