British author (1797–1851) whose first and best-known novel, Frankenstein, or The Modern Prometheus, takes a place among the most enduring classics of the horror genre. Rare partial ALS, one page both sides, 4.5 x 3, October 31, 1832. The signed closing of the letter reads, in full: "I am dear Madam, with every sentiment of respect, truly yrs, Mary Shelley, 31 Oct. 1832." The opposite side, penned in Shelley's hand, in part: "With or without your name as the person to whom they are addressed, your letting me have them would confer an obligation." In very good to fine condition, with light creasing, intersecting folds, and show-through at the corners from small mounting remnants on the reverse. A desirable autograph from the famed author of a horror classic—made all the more desirable by its Halloween date.