 Producer George Pal's attempt was troubled in 1969 by competing views of what the film's story should be, including the possibility of incorporating symbolism of real life issues, in comparison to screenwriter Richard Maibaum's vision.Rewriting Maibaum's screenplay would have taken between two and three months, and the budget would have had to have been reassessed.Pal became concerned the delays would cause the film to miss the wave of success science fiction was enjoying with "" and "Planet of the Apes" in 1968.