If you are a fan of Logan's Run this film is an interesting must see since it plays as a decent prequel (story wise) to that better known sci-fi film. Since LR was made after ZPG I suppose one should say LR plays like a sequel to ZPG. ZPG takes place in an over-populated future so polluted that people wear gas masks outside (we eventually find out it is war related), animals are found only in a museum (stuffed), and food is found only in paste form. The edict: no more babies (or face death), so those born to already pregnant women have an invisible BE (Before Edict) scanned onto their foreheads. In Logan's Run, much later in the future, babies have small crystals placed in their palms that light when the human turns 30. In ZPG we are introduced to a couple (Oliver Reed and Geraldine Chaplin) who work and live as a 1971 typical swinging couple exhibit in the museum along with another couple (best friends/neighbors). When the couple decides to have a baby anyway they are forced to share it with their neighbors or face certain death. There is a scene where Oliver Reed is checking out premature births in a futuristic library very reminiscent of the scene in Logan's Run where Logan researches Sanctuary. Both films deal with escaping the restrictions of a society so messed up it restricts life itself. Eventually the film becomes an escape picture much like Logan's Run. I can't help but think the baby grows up to be the Peter Ustinov character in Logan's Run. Just a thought.