From Leonard Wolf's The Annotated Frankenstein
The preface was entirely written by Percy Shelley, perhaps as part of his sense of obligation to the publishers, Lackington, Allen and Company of London, whom he had assured that "as to any mere inaccuracies of language, I should feel myself authorized to amend them when revising proofs." On October 1817, he wrote to Lackington that "on my part I shall of course do my utmost (for my friend) . . . I have paid considerable attention to the correction of such few instances of baldness of style as necessarily occurs in the production of a very young writer."