Take a look at these writers on writing:
Ray Bradbury- Zen in the Art of Writing
Neil Gaiman - The View from the Cheap Seats
John Gardner - On Becoming a Novelist and The Art of Fiction
Stephen King- On Writing
Anne Lamott- Word By Word
James Michener- My Lost Mexico
Mary Oliver - Rules for the dance : a handbook for writing and reading metrical verse
Mary Oliver - A poetry handbook
Kurt Vonnegut - Like Shaking Hands with God: A Conversation about Writing
Eudora Welty- On Writing
The Paris Review has a wealth of interviews with famous writers about their craft. And many are freely available online.
