I’ve always been fascinated by Ravel’s remark, when a friend asked how he was getting on with composing his Piano Trio, that he had finished it, and all he needed to do was to invent the themes. This seems to indicate that the structure and the inner shapes must have been crystal clear in his head before he found the notes.
Right now I’m re-reading Flaubert’s ‘Madame Bovary’. The translator, Alan Russell, comments in his preface that Flaubert was an inveterate polisher of his prose, working for ages to create the right rhythm for his sentences. As Flaubert neared the end of ‘Madame Bovary’, he commented that he could hear ‘the fall of the phrases’ for pages ahead, before he actually had the words. As a musician, I find this quite haunting to imagine.