I bought this video because it appeared to be based on the book UP PERISCOPE writen by Robb White. I bought the book in about 1961 in grade school. I loved the book and read it several times. The movie has the same characters, Kenn Braden, Skipper Stevensen, Pat Malone, Si, etc. It roughly followed the book, except there was a big difference in one outcome. To be honest, I liked the book more, but I really enjoyed the movie. I think I would have enjoyed it more if I had not read that book and tried to follow the two plots. It was a good movie, but, like the one goat said to the other goat as they were eating the film from a movie "I liked the book better!" Robb White also wrote a book called SECRET SEA, which I enjoyed almost as much as UP PERISCOPE.