 Since Frankenstein was published anonymously in 1818 , readers and critics argued over its origins and the contributions of the two Shelleys to the book . There are differences in the 1818 , 1823 , and 1831 editions , and Mary Shelley wrote , " I certainly did not owe the suggestion of one incident , nor scarcely of one train of feeling , to my husband , and yet but for his incitement , it would never have taken the form in which it was presented to the world . " She wrote that the preface to the first edition was Percy 's work " as far as I can recollect . " James Rieger concluded Percy 's " assistance at every point in the book 's manufacture was so extensive that one hardly knows whether to regard him as editor or minor collaborator " , while Anne K. Mellor later argued Percy only " made many technical corrections and several times clarified the narrative and thematic continuity of the text . " 
