It can be said of very few books that the world was changed as a result of its publication - but this is certainly the case of Capital: A Critique of Political Economy by Karl Marx (1818-1883). Volume 1 appeared (in German) in 1867, and the two subsequent volumes appeared at later dates after the author's death - completed from extensive notes left by Marx himself.

A Treatise of Human Nature is the first work ever published by David Hume, a man who revolutionized our understanding of philosophy. Hume was an advocate of the skeptical school of philosophy and a key figure in the Scottish Enlightenment. He looks at the nature of human experience and cognition, showing that philosophy and reason can only be reflections of our nature.

The foundation for all modern economic thought and political economy, The Wealth of Nations is the magnum opus of Scottish economist Adam Smith, who introduces the world to the very idea of economics and capitalism in the modern sense of the words.

Born out of the political turmoil of the English Civil War, Leviathan stands out as one of the most in influential political and philosophical texts of the 17th century. It argues for the restoration of the monarchy in light of the republic and calls for a commonwealth ruled by an authoritative, autocratic figure with absolute sovereignty. This would put an end to all controversy, war, and fear and establish peace via social contract.

Often considered the foundation of political liberalism, John Locke's Two Treatises of Government was first published anonymously in 1689, in the wake of England's Glorious Revolution. In The First Treatise of Government, Locke refutes the idea of divine monarchy, while The Second Treatise of Government articulates Locke's philosophy of government, which he based upon his theories of natural rights and the social contract.

Schopenhauer was just 30 when his magnum opus, Die Welt als Wille und Vorstellung, a work of considerable learning and innovation of thought, first appeared in 1818.

Much to his chagrin and puzzlement (so convinced was he of its merits), it didn't have an immediate effect on European philosophy, views and culture. It was only decades later that it was recognised as one of the major intellectual landmarks of the 19th century.

Following Marx’s death in 1883, Engels was able to step into the breach and, drawing on Marx’s extensive notes and writings, complete volume 2 of Capital, leading to its publication in 1885. Here, Marx turns his attention to the money owner, the money lender, the wholesale merchant, the trader and the entrepreneur or 'functioning capitalist.'  

Man is born free, and everywhere he is in chains. In The Social Contract, Rousseau explores the concept of freedom and the political structures that may enable people to acquire it. He argues that the sovereign power of a state lies not in any one ruler but in the will of the general population. Rousseau argues that the ideal state would be a direct democracy where executive decision making is carried out by citizens who meet in assembly, as they would in the ancient city-state of Athens.

What is life? What is my place in it? What choices do these questions obligate me to make? More than a half-century after it burst upon the intellectual scene - with roots that extend to the mid-19th century - Existentialism's quest to answer these most fundamental questions of individual responsibility, morality, and personal freedom, life has continued to exert a profound attraction.

First published in 1936, Keynes’ ideas had evolved during the difficulties following World War 1 in Europe, and the US crash and the Depression of the 1920s-'30s and the misery of mass unemployment. He deplored the situation where a few individuals or companies stored massive wealth while vast numbers experienced poverty and insecurity (his alarm bells ring today!) and sought to promote initiatives where governments could intervene with social projects to keep money fluctuating.  

The Republic poses questions that endure: What is justice? What form of community fosters the best possible life for human beings? What is the nature and destiny of the soul? What form of education provides the best leaders for a good republic? What are the various forms of poetry and the other arts, and which ones should be fostered and which ones should be discouraged? How does knowing differ from believing?

I hate every wave of the ocean', the seasick Charles Darwin wrote to his family during his five-year voyage on the H.M.S. Beagle. It was this world-wide journey, however, that launched the scientists career.

The Theory of Moral Sentiments (1759) was the first major text by Adam Smith who, seven years later, was to publish what was to become one of the major economic classics, The Wealth of Nations (1776). However, Smith regarded The Theory of Moral Sentiments as his most important work because in it he identified the profound human instinct to act not necessarily in self-interest but through, as he phrased it, a ‘mutual sympathy of sentiments’. 

Rüdiger Safranski's Goethe: Life as a Work of Art is the first definitive biography in a generation to tell the larger-than-life story of the writer considered to be the Shakespeare of German literature. Drawing upon the trove of letters, diaries, and notebooks Goethe left behind, as well as correspondence and criticism from Goethe's contemporaries, Safranski weaves a rich tale of Europe in the throes of revolution and of the man whose ideas heralded a new era. 

Aristotle’s Organon comprises six key essays on logic, initially collected by Theophrastus, his successor as head of the Peripatetic school, and given its final form by Andronicus some three centuries later. The six essays are: Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics and On Sophistical Refutations. One of the principal topics of Aristotle’s focus is syllogism, in which two premises (one major, one minor) lead to a conclusion. This features in Prior Analytics and On Interpretation.