[1][2][3] Douglas Heyes' screenplay (written under his frequent pseudonym, Matthew Howard) was adapted very freely from L. P. Davies' 1968 novel, The Alien.

In fact, he claims no memory of his life at all, though he has brief dreams of children playing near the ruins of a Greek temple and a woman struggling in water.

Despite Tuxan's brutal interrogation techniques (consisting of electro-shock, water submersion, and execution threats) Welles still maintains his story of total amnesia.

Bellamy, feeling that life was no longer worth living or remembering, volunteered to have his memory wiped via surgery and to play Welles.

Universal bought film rights in June 1968 prior to publication and assigned Dick Berg to produce.

[6] In July 1971 Universal announced that Michael Sarrazin and George Peppard would star in a film version called The Plastic Man.