John Gray was a follower of Adam Smith, David Ricardo and Abram Combe. He was interested in social reform and along with Thomas Hodgskin and John Francis Bray was one of the so called Ricardian Socialists that believed labour was the source of value. Gray wrote several books including Lectures on Human Happiness (1825), The Social System: A Treatise on the Principle of Exchange (1831), An Efficient Remedy for the Distress of Nations (1842), The Currency Question (1847) and Lectures on the Nature and Use of Money (1848).
Gray first wrote to Owen on 1823 when he realised that they shared similar ideas and thereafter he visited New Lanark. However, by 1823 he had become disillusioned by Owen and they publicly fell out.