In Frankenstein, what is the man's background? (Do we now his name yet? Where is he from?)

One can assume, from the question, that the "man" referred to is found in the four opening letters of Mary Shelley's Frankenstein. Given that Walton only refers to the man as "the man" or "the stranger," readers are not directly told who the man Walton has found is.

Once the narrative is "given over" to the man (in all actuality, Walton is the sole narrator of the novel--telling the tale of Victor and of Victor telling the creature's tale), readers are only then told that the character is Victor.

Chapter one opens with the stranger telling Walton about the history of his family and their Genevese background. In reality, it is not until chapter three where the name Frankenstein is actually used: "So much has been done, exclaimed the soul of Frankenstein."