Anyone who has read New Grub Street will know that the difficulties of making a living writing books have been around for a long time. Some writers are blessed with private incomes, rich spouses or a love of asceticism that leaves them unhindered in the pursuit of the literary life. Others rely on a tenured post in academia, with its encouragement to spend extensive periods in well-stocked libraries, archives and manuscript stores, to supplement meagre earnings from scholarship. Many writers of non-fiction have to fit in literary work with a day job, such as journalism or broadcasting or (in the manner of T S Eliot) working in an office. It limits the time one can spend in archives, and if one wishes to write books using original material – and it is always pleasing if one can – that imposes a serious restraint. I have the good fortune to be able to spend one day a week in archives researching my next book, but I am still squeezed for time. Others are less fortunate: researching a book means forgoing the annual holiday or going part-time and never hoping to recoup lost earnings.