Melmoth the Wanderer (Lock and Key Version‪)‬

The central character, Melmoth (a Wandering Jew type), is a scholar who sells his soul to the devil in exchange for 150 extra years of life; he spends that time searching for someone who will take over the pact for him. The novel takes place in the present but the backstory is revealed through several nested stories-within-a-story that work backwards through time.