I know her so well, yet do not know her name. With inferior novels the opposite is often true - to know all too well a character's name, but not ever come to really know the character. "Rebecca" is definitely not an inferior novel. From the first line - the dream of Manderley - to the last glimpse of the mansion in ruins, the reader comes to know the unnamed character as well as any "Juliet Capulet or Jane Eyre. The first person narrative has alway s made me want to insert my own name as I read. From my very first reading of this novel - when I was a pre-teen - to my most recent, now decades later, I beame and continue to feel intimately connected to "the second Mrs. de Winter."
So seamlessly does Du Maurier carry off the "nameless" conceit that, particularly on first reading, one is almost certain they know the character's full name. Her name feels quite as real, and known, as the title character's. I remember spending some time after my initial reading searching for the narrator's Christian name. Part of the genius of this device comes from the fact that most of the people who actually speak to "the second Mrs. de Winter" are servants who would quite naturally only refer to her as Mrs. de Winter, The other person who speaks to her most often is her husband, who, also, quite naturally, refers to her as "Darling," or some other such endearment.
I have always been partial to "the second Mrs. de Winter." Especially her name.