Also in 1966, Kenneth E. Boulding, who was influenced by reading Henry George, used the phrase in the title of an essay, "The Economics of the Coming Spaceship Earth". Boulding described the past open economy of apparently illimitable resources, which he said he was tempted to call the "cowboy economy", and continued: "The closed economy of the future might similarly be called the 'spaceman' economy, in which the earth has become a single spaceship, without unlimited reservoirs of anything, either for extraction or for pollution, and in which, therefore, man must find his place in a cyclical ecological system".