The end of the Cold War, which occurred early in the 1990s, brought joy and freedom to millions. But it posed a difficult question to the world's governments and to the academics who studied them: how would world order be remade in an age no longer dominated by the competing ideologies of capitalism and communism? Samuel P. Huntington was one of the many political scientists who responded to this challenge by conceiving works that attempted to predict the ways in which conflict might play out in the 21st century, and in The Clash of Civilizations he suggested that a new kind of conflict, one centred on cultural identity, would become the new focus of international relations. Huntington's theories, greeted with scepticism when his book first appeared in the 1990s, acquired new resonance after 9/11. The Clash of Civilizations is now one of the most widely-set and read works of political theory in US universities; Huntington's theories have also had a measurable impact on American policy. In large part, this is a product of his problem-solving skills. Clash is a monument to its author's ability to generate and evaluate alternative possibilities and to make sound decisions between them. Huntington's view, that international politics after the Cold War would be neither peaceful, nor liberal, nor cooperative, ran counter to the predictions of almost all of his peers, yet his position – the product of an unusual ability to redefine an issue so as to see it in new ways – has been largely vindicated by events ever since.

Henry Kissinger’s 2014 book World Order: Reflections on the Character of Nations and the Course of History not only offers a summary of thinking developed throughout a long and highly influential career–it is also an intervention in international relations theory by one of the most famous statesmen of the twentieth century. Kissinger initially trained as a university professor before becoming Secretary of State to President Richard Nixon in 1973 – a position in which he both won the Nobel Peace Prize and was accused of war crimes by protesters against American military actions in Vietnam. While a controversial figure, Kissinger is widely agreed to have a unique level of practical and theoretical expertise in politics and international relations – and World Order is the culmination of a lifetime’s experience of work in those fields. The product of a master of the critical thinking skill of interpretation, World Order takes on the challenge of defining the worldviews at play in global politics today. Clarifying precisely what is meant by the different notions of ‘order’ imagined by nations across the world, as Kissinger does, highlights the challenges of world politics, and sharpens the focus on efforts to make surmounting these divisions possible. While Kissinger’s own reputation will likely remain equivocal, there is no doubting the interpretative skills he displays in this engaging and illuminating text.

C. Wright Mills’s 1959 book The Sociological Imagination is widely regarded as one of the most influential works of post-war sociology. At its heart, the work is a closely reasoned argument about the nature and aims of sociology, one that sets out a manifesto and roadmap for the field. Its wide acceptance and popular reception is a clear demonstration of the rhetorical power of Wright’s strong reasoning skills. In critical thinking, reasoning involves the creation of an argument that is strong, balanced, and, of course, persuasive. In Mills’s case, this core argument makes a case for what he terms the “sociological imagination”, a particular quality of mind capable of analyzing how individual lives fit into, and interact with, social structures. Only by adopting such an approach, Mills argues, can sociologists see the private troubles of individuals as the social issues they really are. Allied to this central argument are supporting arguments for the need for sociology to maintain its independence from corporations and governments, and for social scientists to steer away from ‘high theory’ and focus on the real difficulties of everyday life. Carefully organized, watertight and persuasive, The Sociological Imagination exemplifies reasoned argument at its best.

Richard Dawkins provides excellent examples of his reasoning and interpretation skills in The Selfish Gene. His 1976 book is not a work of original research, but instead a careful explanation of evolution, combined with an argument for a particular interpretation of several aspects of evolution. Since Dawkins is building on other researchers’ work and writing for a general audience, the central elements of good reasoning are vital to his book: producing a clear argument and presenting a persuasive case; organising an argument and supporting its conclusions. In doing this, Dawkins also employs the crucial skill of interpretation: understanding what evidence means; clarifying terms; questioning definitions; giving clear definitions on which to build arguments. The strength of his reasoning and interpretative skills played a key part in the widespread acceptance of his argument for a gene-centred interpretation of natural selection and evolution – and in its history as a bestselling classic of science writing.

Few historical problems are more baffling in retrospect than the conundrum of how Hitler was able to rise to power in Germany and then command the German people – many of whom had only marginal interest in or affiliation to Nazism – and the Nazi state. It took Ian Kershaw – author of the standard two-volume biography of Hitler – to provide a truly convincing solution to this problem. Kershaw's model blends theory – notably Max Weber's concept of ‘charismatic leadership’ – with new archival research into the development of the Hitler ‘cult’ from its origins in the 1920s to its collapse in the face of the harsh realities of the latter stages of World War II. Kershaw’s model also looks at dictatorship from an unusual angle: not from the top down, but from the bottom up, seeking to understand what ordinary Germans thought about their leader. Kershaw's broad approach is a problem-solving one. Most obviously, he actively interrogates his evidence, asking highly productive questions that lead him to fresh understandings and help generate solutions that are credibly rooted in the archives. Kershaw’s theories also have application elsewhere; the model set out in The ‘Hitler Myth’ has been used to analyse other charismatic leaders, including several from ideologically-opposed backgrounds.

The essay for which The Sacred Wood is primarily remembered is one of the most famous pieces of criticism in English: “Tradition and the Individual Talent” helped to re-orientate arguments about the study of literature and its production by redefining the nature of tradition and the artist's relation to it.At a time when the word “traditional” had become a way of damning with faint praise by reference to the past, Eliot reinterpreted the term to mean something entirely different. It is not, he argues, something just “handed down,” but, instead, a prize to be obtained “by great labour,” not least in the making of a huge effort of understanding how the past fits together. Seen thus, Eliot suggests, a literary and artistic tradition “has a simultaneous existence and composes a simultaneous order” – and it is not just past, but present as well. For Eliot, “art never improves,” but only changes, and each part of the tradition is constantly being reinterpreted in light of what is added to the whole. The role of the poet, in Eliot's view, is to subjugate their own personality, and become “a receptacle,” in which “numberless feelings, phrases, images... can unite to form a new compound.” Redefining the issue of poets' relations to the past in this new way is a fine example of creative thinking, and Eliot’s ability to connect existing concepts in new ways was what gave weight to the argument that he advanced: that poets cannot succeed without understanding that they are taking their place on a continuum that stretches back to all their predecessors, and incorporate the ideas, strengths and failings of the entire body of work that those poets represented.

Understanding why revolutions take place when they do, and as they do, is important in itself. Understanding how they are rooted in the societies they upend – and the ways in which those societies share crucial similarities – is arguably even more so. The enduring influence of Jack Goldstone's Revolution and Rebellion lies as much in the challenge that it issues to the long-dominant model of ‘western exceptionalism’ (the idea that it was early modern Europe's distinctive history that launched it on the path to world domination) as it does in the book's persuasive account of revolutions rooted in a four stage process that advances from fiscal crisis, through inter-elite conflict and mass-mobilization potential, to the breakdown and re-making of culture and ideology. It can be argued that this unexpected outcome – one that the author himself did not anticipate – is the product of an acute problem-solving ability, one that made Goldstone particularly receptive to alternative possibilities. His insistence that early modern and modern European and Asian peoples have vastly more in common than was generally recognised, and followed a similar path of advanced organic development that left Qing China as vulnerable to revolution as the France of the Ancien Régime, has not only become a central contention of early 21st century sociology; it has also underpinned the creation of multiple theoretical models that have nothing to do with revolution. None of this would have been possible had not Goldstone challenged himself by asking questions that other scholars had supposed had mundane answers.

Adam Smith’s 1776 Inquiry into The Nature and Causes of the Wealth of Nations – more often known simply as The Wealth of Nations – is one of the most important books in modern intellectual history. Considered one of the fundamental works of classical economics, it is also a prime example of the enduring power of good reasoning, and the ability of reasoning to drive critical thinking forward. Adam Smith was attempting to answer two complex questions: where does a nation’s wealth come from, and what can governments do to increase it most efficiently? At the time, perhaps the most widely accepted theory, mercantilism, argued that a nation’s wealth was literally the amount of gold and silver it held in reserve. Smith, meanwhile, weighed the evidence and came to a different conclusion: a nation’s wealth, he argued, lay in its ability to encourage economic activity, largely without government interference. Underlying this radical redefinition was the revolutionary concept that powered Smith’s reasoning and which continues to exert a vast influence on economic thought: the idea that markets are self-regulating. Pitting his arguments against those of his predecessors, Smith carefully and persuasively reasoned out a strong case for free markets that reshaped government economic policies in the 19th-century and continues to shape global prosperity today.

Sun Tzu's The Art of War is a series of lessons in the applied art of problem solving. Sun (544 BC-496 BC), an experienced general from the Warring States period of Chinese history, saw war as an inevitable problem – indeed, the ultimate problem confronting the state. The Art of War summarises his lessons on how to solve the problems raised by conflict. The work comprises a series of pithy discussions of the different strategic situations that might arise, and the best responses for each. In many ways it is a masterclass in the application of critical thinking to practical affairs. Aspiring generals are advised to 'appraise the situation' according to five separate criteria, and to plan accordingly. 'The expert at battle seeks his victory from strategic advantage', Sun writes, so every general must assess their situation from every angle, and establish not only the best way to give themselves the strategic advantage – but also of preventing the other side from giving itself the advantage. Throughout the text, Sun epitomises the qualities of a good problem solver by focusing on the nature of the problem; asking productive questions about it; and making sound decisions.

There is arguably no more famous book about the arts of interpretation and analysis than Sigmund Freud’s 1899 Interpretation of Dreams. Though the original edition of just 600 copies took eight years to sell out, it eventually became a classic text that helped cement Freud’s reputation as one of the most significant intellectual figures of the 19th and 20th centuries. In critical thinking, just as in Freud’s psychoanalytical theories, interpretation is all about understanding the meaning of evidence, and tracing the significance of things. Analysis can then be brought in to tease out the implicit reasons and assumptions that lie underneath the interpreted evidence. Interpretation of Dreams is a masterclass in building telling analyses from ingenious interpretation of evidence. Freud worked from the assumption that all dreams were significant attempts by the unconscious to resolve conflicts. As a result, he argued, they contain in altered and disguised forms clues to our deepest unconscious urges and desires. Each must be taken on its own terms to tease out what they really mean. Though Freud’s theories have often been criticized, he remains the undisputed master of interpretation – with his critics suggesting that he was, if anything, too ingenious for his own good.