Alexander Hartdegen is a fictional character from the science fiction novel "The Time Machine," written by H.G. Wells. He is a scientist and inventor who becomes obsessed with the concept of time travel after a personal tragedy. His character represents the pursuit of knowledge and the consequences of tampering with time. In the story, Hartdegen builds a time machine and travels to the distant future, where he encounters different societies and the evolution of humanity. His journey explores themes of progress, the nature of time, and the impact of technology on society.