Melvyn Bragg and guests discuss the formation of the Royal Society. In the 17th century the natural philosopher Francis Bacon heralded the new age of science. The frontispiece to his 1620 edition of the Instauratio Magna depicted a galleon travelling between the metaphorical Pillars of Hercules thought to lie at the Strait of Gibraltar and believed to mark the end of the known world. The image encapsulated Bacon's desire to sail beyond the limits set by Aristotle and the curriculum of the Ancient universities towards the new continent of science. Bacon imagined practical scientists engaged in a collaborative effort to expand knowledge of the natural world. But it was not until the turbulence of the Civil War and Commonwealth years had passed that such a group of scientists would gather together in London for this purpose, and form the Royal Society. Amongst its members were Robert Boyle, Robert Hooke, Christopher Wren and Isaac Newton, who explicitly rejected dogma and insisted on practical experimentation and observation. How was the Royal Society formed against a backdrop of religious and political strife? What was it about the way this group of men worked that allowed each individual to flourish in his own field? How successful was the Royal Society in disseminating the benefits of experimental science and what is its enduring legacy? With Stephen Pumfrey, Senior Lecturer in the History of Science at the University of Lancaster; Lisa Jardine, Professor of Renaissance Studies at Queen Mary, University of London; Michael Hunter, Professor of History at Birkbeck, University of London.

Melvyn Bragg and guests discuss Miguel de Cervantes’ 17th century novel, Don Quixote. Published four hundred years ago in Madrid, the book was an immediate success and recognised as one of the classic texts of Western Literature, revered by writers such as Sterne, Goethe, Flaubert, Dostoevsky, Kafka and Melville. Don Quixote tells the story of an unlikely hero - an impoverished country gentleman who goes mad from reading too much and decides to put the world to rights by becoming a knight errant. And so the Knight of La Mancha tilting at windmills with his portly squire astride a donkey is one of the most enduring images in the popular imagination but the simple comedy of the affair belies the fantastically complex, beguiling and sophisticated story on which it is based. As Don Quixote's delusional chivalric ideals bump up against the humdrum of reality and the views of his more earth-bound companion, Sancho Panza.So how has the book endured over the centuries? What was the relationship between Cervantes' work and the world of 17th century Spain in which he lived? In what ways was Don Quixote an interpretation of the age which hitherto had not been articulated? And can it live up to the claim that it was the first European novel?With Barry Ife, Cervantes Professor Emeritus at King's College London; Edwin Williamson, Professor of Spanish Studies at the University of Oxford; Jane Whetnall, Senior Lecturer in Hispanic Studies at Queen Mary, University of London.

Melvyn Bragg and guests discuss negative numbers, a history of mystery and suspicion. In 1759 the British mathematician Francis Maseres wrote that negative numbers "darken the very whole doctrines of the equations and make dark of the things which are in their nature excessively obvious and simple". Because of their dark and mysterious nature, Maseres concluded that negative numbers did not exist, as did his contemporary, William Friend. However, other mathematicians were braver. They took a leap into the unknown and decided that negative numbers could be used during calculations, as long as they had disappeared upon reaching the solution. The history of negative numbers is one of stops and starts. The trailblazers were the Chinese who by 100 BC were able to solve simultaneous equations involving negative numbers. The Ancient Greeks rejected negative numbers as absurd, by 600 AD, the Indians had written the rules for the multiplication of negative numbers and 400 years later, Arabic mathematicians realised the importance of negative debt. But it wasn't until the Renaissance that European mathematicians finally began to accept and use these perplexing numbers. Why were negative numbers considered with such suspicion? Why were they such an abstract concept? And how did they finally get accepted? With Ian Stewart , Professor of Mathematics at the University of Warwick; Colva Roney-Dougal , Lecturer in Pure Mathematics at the University of St Andrews; Raymond Flood , Lecturer in Computing Studies and Mathematics at Kellogg College, Oxford.

Melvyn Bragg and guests discuss the concept of friendship. In Greek and Roman times, friendship was thought of as being an essential constituent of both a good society and a good life; a good society because it lay at the heart of participative civic democracy; a good life because it nurtured wisdom and happiness. It is this period which gives us the texts on friendship which, to this day, are arguably the most important of their kind. Amongst their authors is Aristotle, who engaged in one of the great philosophical discussions on the subject. For Aristotle, friendship could fall into three categories: it could be based on utility, pleasure or goodness. In its latter state, Aristotle described it as being 'a single soul dwelling in two bodies'. So how did the Ancients establish the parameters of the true nature of friendship in the literature and philosophy that followed? How have different forms of friendship helped or hindered creativity and intellectual pursuit? What has been the apparent relationship between friendship and power? And what of the darker aspects of friendship - jealousy, envy and exploitation? With Angie Hobbs, Lecturer in Philosophy at the University of Warwick; Mark Vernon, Visiting Lecturer in Philosophy at Syracuse University and London Metropolitan University; John Mullan, Professor of English at University College London.

Melvyn Bragg and guests discuss Catherine the Great. In Moscow's Tretyakov Gallery hangs perhaps the most well-known picture of Russia's most well-known ruler. Dimitri Levitsky's 1780 'Portrait of Catherine the Great in the Justice Temple' depicts Catherine in the temple burning poppies at an altar, symbolising her sacrifice of self-interest for Russia. Law books and the scales of justice are at her feet, highlighting her respectful promotion of the rule of law. But menacingly, in the background an eagle crouches, suggesting the means to use brutal power where necessary. For an obscure, small-town German princess Catharine’s ambition was large - the transformation of semi-barbaric Russia into a model of the ideals of the French 18th century Enlightenment. How far was Catherine able to lead her country into full participation in the political and cultural life of Europe? Was she able to liberate the serfs? And should she be remembered as Russia's most civilised ruler or a megalomaniacal despot? With Janet Hartley, Professor of International History at the London School of Economics; Simon Dixon, Professor of Modern History at the University of Leeds; Tony Lentin, Professor of History at the Open University.

Melvyn Bragg and guests discuss the story of human evolution, which stretches back over six million years. It is not the story of one species but of several diverse species, some of whom walked the Earth at the same time. From the earliest hominids to the early Homo sapiens, there was nothing inevitable about the course of human evolution. But what conditions created the opportunity for diverse human species to thrive? What environmental factors led to the survival of one human species, but contributed to the extinction of so many others? What can the fossil record and the science of genetics tell us about our ancestors? How does the brain make modern man so unique in the natural world? With Steve Jones, Professor of Genetics in the Galton Laboratory at University College London; Fred Spoor, Professor of Evolutionary Anatomy at University College London; Margaret Clegg, Honorary Research Fellow in the Department of Biological Anthropology at University College London.

Melvyn Bragg and guests discuss Geoffrey Chaucer, often called the father of English literature."In Southwark at the Tabard as I lay Redy to wenden on my pilgrymage To Canterbury with ful devout corage, At nyght was come into that hostelrye Wel nyne and twenty in a compaignye Of sundry folk, by aventure yfalle In felaweshipe, and pilgrims were they alle, That toward Canterbury wolden ryde." Geoffrey Chaucer immortalised the medieval pilgrimage and the diversity of 14th century English society in his Canterbury Tales. As each pilgrim takes his, or her, turn to tell their tale on the road to Canterbury, Chaucer brings to life the voices of a knight, a miller, a Wife of Bath and many more besides. Chaucer was born the son of a London vintner, yet rose to high office in the court of Richard II. He travelled throughout France and Italy where he came into contact with the works of Dante, Boccaccio, Machaut and Froissart. He translated Boethius, wrote dream poetry, a defence of women and composed the tragic masterpiece Troilus and Criseyde. As well as the father of English literature, Chaucer was also a philosopher, bureaucrat, courtier and diplomat.So what do we know of Chaucer? How did he introduce the themes of continental writing to an English speaking audience? And why does his poetry still seem to speak so directly to us today? With Carolyne Larrington, Tutor in Medieval English at St John's College, Oxford; Helen Cooper, Professor of Medieval and Renaissance English at the University of Cambridge; Ardis Butterfield, Reader in English at University College London.

Melvyn Bragg and guests discuss the Abbasid Caliphs, dynastic rulers of the Islamic world from the mid eighth to the tenth century. They headed a Muslim empire that extended from Tunisia through Egypt, Syria, Arabia, and Persia to Uzbekistan and the frontiers of India. But unlike previous conquerors, the Abbasid Caliphs presided over a multicultural empire where conversion was a relatively peaceful business. As Vikings raided the shores of Britain, the Abbasids were developing sophisticated systems of government, administration and court etiquette. Their era saw the flowering of Arabic philosophy, mathematics and Persian literature. The Abbasids were responsible for patronising the translation of Classical Greek texts and transmitting them back to a Europe emerging from the Dark Ages. So who were the Abbasid Caliphs and how did they come to power? What was their cultural significance? What factors can account for their decline and fall? And why do they represent a Golden Age of Islamic civilisation? With Hugh Kennedy, Professor of History at the University of St Andrews; Robert Irwin, Senior Research Associate at the School of Oriental and African Studies; University of London; Amira Bennison, Senior Lecturer in Middle Eastern and Islamic Studies at the University of Cambridge.

Melvyn Bragg and guests discuss 17th century print culture."Away ungodly Vulgars, far away, Fly ye profane, that dare not view the day, Nor speak to men but shadows, nor would hear Of any news, but what seditious were, Hateful and harmful and ever to the best, Whispering their scandals ... " In 1614 the poet and playwright George Chapman poured scorn on the popular appetite for printed news. However, his initial scorn did not stop him from turning his pen to satisfy the public's new found appetite for scandal. From the advent of the printing press the number of books printed each year steadily increased, and so did literacy rates. With a growing and socially diverse readership appearing over the sixteenth and seventeenth centuries, printed texts reflected controversy in every area of politics, society and religion. In the advent of the Civil War, print was used as the ideological battleground by the competing forces of Crown and Parliament. What sorts of printed texts were being produced? How widespread was literacy and who were the new consumers of print? Did print affect social change? And what role did print play in the momentous English Civil War? With Kevin Sharpe, Professor of Renaissance Studies at Queen Mary, University of London; Ann Hughes, Professor of Early Modern History at the University of Keele; Joad Raymond, Professor of English Literature at the University of East Anglia.

Melvyn Bragg and guests discuss relativism, a philosophy of shifting sands. "Today, a particularly insidious obstacle to the task of educating is the massive presence in our society and culture of that relativism which, recognizing nothing as definitive, leaves as the ultimate criterion only the self with its desires. And under the semblance of freedom it becomes a prison for each one, for it separates people from one another, locking each person into his or her own 'ego'." Pope Benedict XVI, in a speech given in June 2005, showed that the issue of relativism is as contentious today as it was in Ancient Greece, when Plato took on the relativist stance of Protagoras and the sophists. Relativism is a school of philosophical thought which holds to the idea that there are no absolute truths. Instead, truth is situated within different frameworks of understanding that are governed by our history, culture and critical perspective. Why has relativism so radically divided scholars and moral custodians over the centuries? How have its supporters answered to criticisms that it is inherently unethical? And if there are universal standards such as human rights, how do relativists defend culturally specific practices such as honour killings or female infanticide? With Barry Smith, Senior Lecturer in Philosophy at Birkbeck College, University of London; Jonathan Rée, freelance philosopher who holds visiting professorships at the Royal College of Art and Roehampton University; Kathleen Lennon, Senior Lecturer in Philosophy at the University of Hull.