Who finshed writing Dr. Seuss' last book?

Um, is this a trick question? If it was Dr. Seuss' last book, then Dr. Seuss (Theodor Geisel) wrote it. They have some books where they use his name as part of the series, but he isn't listed as the author unless he wrote it. Here is a list of his books (as Dr. Seuss): http://en.wikipedia.org/wiki/List_of_Dr._Seuss_books Here is a list of other books he wrote with other pseudonyms: http://en.wikipedia.org/wiki/Dr._Seuss#List_of_books