Part of Brain Pickings is devoted to him.
I am moved to quote him:
“The act of writing is an integral part of my mental life; ideas emerge, are shaped, in the act of writing… a special, indispensable form of talking to myself.”
He did what all writers do (and I include myself) - we call on the fundus (prop cupboard), dregs, bits and pieces and individuals we have experienced, wanted to experience, or are glad not to have experienced and anoint/appoint fictional characters with them. We invent lovers, friends, family, even enemies as we need them. We are in charge - sort of.