1) Moon-Watcher - One of the most innately gifted man-apes. Moon-Watcher demonstrates the ability to walk upright and to engage in crude planning. His mind is pushed along a bit further by the black monolith. He is the first person to kill another being for food.
             Dr. Heywood Floyd - A senior government official and ex-scientist. Floyd is sent to the moon to investigate TMA. He is an effective bureaucrat and an extremely wise scientist. He is one of the first men to see TMA-1 and to wonder about its intentions.
             Ralph Halvorson - The Administrator of the Southern Province of the Moon. He is said to be the security guard. Ralph is another of the book's bureaucrats, the man who greets Dr. Floyd on his arrival to the moon.
             David Bowman - A broadly skilled astronaut. David Bowman is chosen as one of two crew members to stay awake during the entire voyage to Saturn. He is intelligent and disciplined, which helps him survive the loneliness of Poole's death. He passes through the Star Gate never to be heard of again.
             Frank Poole - The other astronaut who is awake for the entire journey to Saturn. Poole is mechanically skilled and is the one who makes extra-vehicular trips, one of which ultimately results in his death.
             Hal - A robot, created in a lab, Hal is not human, but he is intelligent. He can carry on a conversation just as a human. Being a robot, however, he can also perform complex calculations and does not require sleep or food. He can play chess, but has been programmed to lose 50% of the time so that morale of the player does suffer. As he becomes self-conscious of his being, he develops a guilty and, ultimately, murderous intentions in an attempt to preserve his existence.
             2) The most important problem that the main character confronted was HAL, the malfunctioning super-computer. When HAL informs Poole that the AE-35 unit (the unit that controls the radio connection to Earth) may malfunction within 72 hours,
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