Albert Allen Bartlett was a professor of physics at the University of Colorado Boulder who spent his career talking about an important math concept called exponential growth. Exponential growth means that something grows very quickly to the point where it's too big for us to handle. For example, if you start with one penny and double it every day for 30 days, you would have over 5 million pennies at the end! That's exponential growth.
Albert Bartlett wanted to help people understand how important it is to limit the amount of things like pollution and population growth, because they can quickly become too big for us to handle if they grow too fast. He wrote books and gave lots of lectures so people could learn about this concept and help make our world a better place.