<human>:  When did the Limits to Growth first come out?
<bot>: The Limits to Growth was a book by a group of scientists that came out in 1972. It was a study of the global economy that tried to predict the future of the world economy. The study was a bit of a flop, as the authors predicted a worldwide economic collapse in the 1970s, but the world economy has continued to grow and thrive since then.