If you haven't discovered them, I highly recommend a visit to the Paris Review archive of interviews.
This New York-based quarterly began interviewing authors and poets in 1953 (EM Forster was first) and they have amassed a trove of fascinating and irreplaceable records. I've been reading them quite systematically, going backwards from the 2000s and hugely enjoying not only the theoretical or critical or historical reflections, but also their descriptions of how and when they write: pen or computer, morning or evening, quiet place or town square; how many words a day, how often, how methodically etc. All different, but some common themes emerge: most writers born pre-1970 write first in longhand, eschewing even the typewriter, let alone the word processor. Nearly all say writing requires and rewards solitude. Nearly all say it's not easy. In fact Thomas Mann said “a writer is a person for whom writing is more difficult than it is for other people.” This seems to be true.`
My favourites so far: Marilynne Robinson (predictably), Stephen King (surprisingly), Salmon Rushdie, and Martin Amis. These last three are certainly not favourite authors of mine, but their interviews are frank, funny, engaging, and profitable. Others come across as pompous or pretentious (Umberto Eco) and others exactly as one might have expected having read their books (E Annie Proulx, Hunter S Thompson).
Ironically, in that very first interview, EM Forster said “I am more interested in works than in authors.” Roland Barthes announced the death of the author and ushered in the reader as the central figure of literature, but of late we (as readers) have shown an insatiable interest in biography, memoir, diary and other kinds of life writing. We are intrigued by the celebrity author as well as by the recluse, and the book tour is these days the inevitable corollary of the book.
More than a glimpse of the private lives of authors, these interviews contain the reflections of successful practitioners of literature on their craft and the state of creativity more broadly. Again, they're all different, but they all offer first hand accounts of their long-hand grapple with the difficulties of writing - difficulties which non-writers don't seem to face, and which seem to constitute both writing's cost and its gift. These interviews should be prized not as pontifications by those with pretensions to knowledge, but as dispatches from the frontline of creativity.