David Harvey is a famous professor and writer who studies and writes about cities, like how they change over time. He is a leading expert on something called "urban studies," which is the study of cities, their history, economy, and culture. He is interested in how cities develop and how they can be improved so that everyone who lives in them has a better quality of life. He also studies the politics of cities and how people’s lives can be improved through better urban planning—like building affordable housing and things like that.