Unusually for a Geore Pal film, this movie does not have at its core the special effects, but rather a wonderful performance by Tony Randall (or more accurately, performances) and the makeup, which received the first Oscar (a special one) ever given for makeup. A good cast and script are also plusses. Read the original novella by Charles G. Finney if you can find it-it's well worth tracking down. Recommended.