Melvyn Bragg and his guests discuss Hadrian's Wall, the largest Roman structure and one of the most important archaeological monuments in Britain. Stretching for eighty miles from the mouth of the River Tyne to the Solway Firth and classified today as a World Heritage Site, it has been a source of fascination ever since it came into existence. It was built in about 122 AD by the Emperor Hadrian, and a substantial part of it still survives today. Although its construction must have entailed huge cost and labour, the Romans abandoned it within twenty years, deciding to build the Antonine Wall further north instead. Even after more than a century of excavations, many mysteries still surround Hadrian's Wall, including its exact purpose. Did it have a meaningful defensive role or was it mainly a powerful emperor's vanity project?

With:

Greg Woolf

David Breeze

Lindsay Allason-Jones

Producer: Victoria Brignell.

Melvyn Bragg and his guests discuss Scepticism, the idea that it may be impossible to know anything with complete certainty. Scepticism was first outlined by ancient Greek philosophers: Socrates is reported to have said that the only thing he knew for certain was that he knew nothing. Later, Scepticism was taught at the Academy founded by Plato, and learnt by students who included the Roman statesman Cicero. The central ideas of Scepticism were taken up by later philosophers and came to the fore during the Renaissance, when thinkers including Rene Descartes and Michel de Montaigne took up its challenge. A central plank of the philosophical system of David Hume, Scepticism had a powerful influence on the religious and scientific debates of the Enlightenment.

With:

Peter Millican

Melissa Lane

Jill Kraye

Producer: Thomas Morris.

Melvyn Bragg and his guests discuss the life and work of the Arab philosopher al-Kindi. Born in the early ninth century, al-Kindi was heavily influenced by Greek philosophy and supervised the translation of many works by Aristotle and others into Arabic. The author of more than 250 works, he wrote on many different subjects, from optics to mathematics, music and astrology. He was the first significant thinker to argue that philosophy and Islam had much to offer each other and need not be kept apart. Today al-Kindi is regarded as one of the greatest scholars of the medieval Islamic world.

With:

Hugh Kennedy

James Montgomery

Amira Bennison

Producer: Thomas Morris.

Melvyn Bragg and his guests discuss the life of the prominent 19th-century social reformer Annie Besant. Born in 1847, Annie Besant espoused a range of causes including secularism, women's rights, Socialism, Irish Home Rule, birth control and better conditions for workers. Described by Beatrice Webb as having "the voice of a beautiful soul", Besant became an eloquent public speaker as well as writing numerous campaigning articles and pamphlets. She is perhaps most famous for the key role she played in the successful strike by female workers at the Bryant and May match factory in East London in 1888, which brought the appalling working conditions of many factory workers to greater public attention.

Later in life she became a follower of theosophy, a belief system bringing together elements of Hinduism, Buddhism and other Eastern religions. She moved to India, its main base, and took on a leading role in the Indian self-rule movement, being appointed the first female president of the Indian National Congress in 1917.

With:

Lawrence Goldman

David Stack

Yasmin Khan

Producer: Victoria Brignell.

Melvyn Bragg and his guests discuss James Joyce's novel Ulysses. First published ninety years ago in Paris, Joyce's masterpiece is a sprawling and startlingly original work charting a single day in the life of the Dubliner Leopold Bloom. Some early readers were outraged by its sexual content and daringly scatalogical humour, and the novel was banned in most English-speaking countries for a decade after it first appeared. But it was soon recognised as a genuinely innovative work: overturning the ban on its publication, an American judge described Ulysses as "a sincere and serious attempt to devise a new literary method for the observation and description of mankind."Today Ulysses is widely regarded as the greatest example of literary modernism, and a work that changed literature forever. It remains one of the most discussed novels ever written.Steven ConnorProfessor of Modern Literature and Theory at Birkbeck, University of LondonJeri JohnsonSenior Fellow in English at Exeter College, OxfordRichard BrownReader in Modern English Literature at the University of LeedsProducer: Thomas Morris.

Melvyn Bragg and his guests discuss the biblical king Solomon, celebrated for his wisdom and as the architect of the First Temple in Jerusalem. According to the Old Testament account of his life, Solomon was chosen as his father David's successor as Israelite king, and instead of praying for long life or wealth asked God for wisdom. In the words of the Authorised Version, "And there came of all people to hear the wisdom of Solomon, from all kings of the earth, which had heard of his wisdom." Solomon is an important figure in Judaism, Islam and Christianity alike, and is also credited with the authorship of several scriptural texts. His name is associated with the tradition of wisdom literature and with a large number of myths and legends. For many centuries Solomon was seen as the archetypal enlightened monarch, and his example influenced notions of kingship from the Middle Ages onwards.With:Martin PalmerDirector of the International Consultancy on Religion, Education, and CulturePhilip AlexanderEmeritus Professor of Jewish Studies at the University of ManchesterKatharine DellSenior Lecturer in Old Testament Studies at the University of Cambridge, and Fellow of St Catherine's College, CambridgeProducer: Thomas Morris.

Melvyn Bragg and his guests discuss the Trojan War, one of the best known events of Greek mythology. According to the traditional version of the story, the war began when a Trojan prince, Paris, eloped with the Spartan queen Helen. A Greek army besieged Troy for ten years before the city was finally overrun and destroyed. Some of the most familiar names of Greek mythology are associated with the war, including Achilles and Hector, Odysseus and Helen of Troy - and it has also given us the story of the Trojan Horse.The war is the backdrop for Homer's epic poem The Iliad, and features in many other works from classical antiquity. For centuries it was assumed to be a mythical event. But in the nineteenth century a series of archaeological discoveries provided startling evidence that Troy might really have existed, leading some scholars to conclude that there could even be some truth behind the myth. So does the Trojan War story have any basis in fact? And why has it proved such an enduring legend?With:Edith HallProfessor of Classics at King's College LondonEllen AdamsLecturer in Classical Art and Archaeology at King's College LondonSusan SherrattLecturer in Archaeology at the University of SheffieldProducer: Thomas Morris.

Melvyn Bragg and his guests discuss the celebrated Venetian explorer Marco Polo. In 1271 Polo set off on an epic journey through Asia. He was away for more than twenty years, and when he returned to Venice he told extraordinary tales of his adventures. He had visited the court of the Mongol Emperor Kublai Khan, and acted as his emissary, travelling through many of the remote territories of the Far East. An account of Marco Polo's travels was written down by his contemporary Rustichello da Pisa, a romance writer he met after being imprisoned during a war against the neighbouring Genoese.The Travels of Marco Polo was one of the most popular books produced in the age before printing. It was widely translated, and many beautifully illustrated editions made their way to the collections of the rich and educated. It was much read by later travellers, and Polo's devotees included Christopher Columbus and Henry the Navigator. For centuries it was seen as the first and best account of life in the mysterious East; but today the accuracy and even truth of Marco Polo's work is often disputed.With:Frances WoodLead Curator of Chinese Collections at the British LibraryJoan Pau RubiesReader in International History at the London School of Economics and Political ScienceDebra Higgs StricklandSenior Lecturer in the History of Art at the University of GlasgowProducer: Thomas Morris.

Melvyn Bragg and his guests discuss On War, a treatise on the theory and practice of warfare written by the Prussian soldier and intellectual Carl von Clausewitz. First published in 1832, Clausewitz's magnum opus is commonly regarded as the most important book about military theory ever written. Informed by its author's experience of fighting against the mighty armies of Napoleon, the work looks not just at the practicalities of warfare, but offers a subtle philosophical analysis of the nature of war and its relationship with politics. Notions such as the Clausewitzian Trinity have had an enormous effect on later military leaders. But its influence is felt today not just on the battlefield but also in politics and business.With:Saul DavidProfessor of War Studies at the University of BuckinghamHew StrachanChichele Professor of the History of War at the University of OxfordBeatrice HeuserProfessor of International Relations at the University of Reading.Producer: Thomas Morris.

Melvyn Bragg and his guests discuss game theory, the mathematical study of decision-making. First formulated in the 1940s, the discipline entails devising 'games' to simulate situations of conflict or cooperation. It allows researchers to unravel decision-making strategies, and even to establish why certain types of behaviour emerge. Some of the games studied in game theory have become well known outside academia - they include the Prisoner's Dilemma, an intriguing scenario popularised in novels and films, and which has inspired television game shows. Today game theory is seen as a vital tool in such diverse fields as evolutionary biology, economics, computing and philosophy. With:Ian StewartEmeritus Professor of Mathematics at the University of WarwickAndrew ColmanProfessor of Psychology at the University of LeicesterRichard BradleyProfessor of Philosophy at the London School of Economics and Political Science.Producer: Thomas Morris.