"The Worlds of If" by Stanley G. Weinbaum is a science fiction short story written in the early 20th century. The narrative blends themes of time travel with speculative concepts about alternate realities, focusing on the idea of "what could have been" had different choices been made. Through a unique machine invented by the protagonist's former professor, the story explores the profound implications of one's decisions on the fabric of reality. Dixon Wells, the protagonist, grapples with feelings of guilt after missing a flight that ultimately ends in disaster, the sinking of the rocket "Baikal". Through a contraption called the "subjunctivisor," which allows users to view alternate realities based on hypothetical decisions, he seeks to understand what would have happened had he boarded the flight. As he engages with the machine, he rekindles memories of a captivating encounter with Joanna Caldwell, a fellow passenger, but is ultimately devastated to discover she survived the crash yet married the man who saved her. This poignant exploration of missed opportunities and the "worlds of if" ultimately leaves Wells to confront his own fate and the consequences of being perpetually late. (This is an automatically generated summary.)