Where can I find something that has authors of books talking about writing, why they do it and how they do it?

I'm writing аn isearch thing οn writing books аnd i need ѕοmе information οn whу people write books, hοw thеу dο іt, whеrе dο thеу gеt thеіr іdеаѕ аnd οthеr things such аѕ thаt. Plz hеlр mе out!