"Cancer World" by Harry Warner, Jr. is a science fiction novel written in the mid-20th century. The book explores a dystopian future where healthy individuals are barred from traveling to Mars to assist in creating a cancer-free population, while those diagnosed with cancer are forcibly relocated to the planet. Central to the story is a man's desperate struggle to stay with his family amidst this oppressive legislation and government control. The narrative follows Greg Marson, who faces turmoil when his wife, Dora, receives news of her cancer diagnosis. As she prepares to leave for Mars with their children, Greg is torn between the harsh laws that prevent him from accompanying them and his urge to ensure his family's safety. This leads him to pursue illegal means to get himself onto Mars, including seeking a dangerous medical procedure to falsify his health status. In a twist of fate, he accidentally ends up on a freighter destined for Venus. Throughout the story, themes of familial loyalty, government overreach, and personal sacrifice are deeply interwoven, culminating in Greg’s realization of the true nature of the population crisis affecting both Mars and Earth. (This is an automatically generated summary.)