Henry Home, Lord Kames, was by nature an advocate for reform and improvement and stood at the heart of the modernizing and liberalizing movement now known as the Scottish Enlightenment. The reaction to his Essays on the Principles of Morality and Natural Religion was a defining moment in the establishment of the predominance of moderation in the Church of Scotland. Divided into three books, Kames's 'Sketches of the History of Man' draws together the concerns of many of his earlier works. The first book considers man in the private sphere and presents Kames's version of the "four-stage theory of history": the progress, that is, from hunting, through 'the shepherd state' to agriculture, and thence to commerce. It contains, in addition, sketches on progress in the arts, taste, manners, and appetite for luxury goods. The second book takes as its subject man in the public sphere and explores the implications of his natural 'appetite for society'. Kames develops the notion that political, legal, and financial institutions are best regulated when it is understood that they are outgrowths of aspects of human nature. In the final book, Kames turns to an account of progress in the sciences of logic, morals, and theology. He seeks to vindicate the claim that "human understanding is in a progress towards maturity, however slow". Throughout the entire work, Kames expounds on his fundamental hypothesis that at the beginning of the history of the human race, savagery was ubiquitous and that the human story is one of an emergence out of barbarism and toward maturity.