Will we recognise the signs that democracy has ended? Cambridge professor David Runciman worries that we spend far too much time comparing today's politics with the 1930s, and that this blinds us to the frailties of democracy today. He tells Amol Rajan why he thinks our current political system will come to an end - and why we may not even notice this happening.Professor Nic Cheeseman is all too aware that democracy can become an empty shell. His new book How To Rig An Election, co-written with Brian Klaas, looks at the myriad ways autocrats use elections for their own ends, from buying votes and bribing electors to issuing fake pens in the ballot box. And it is not only the developing world in which corruption takes place. He addresses the role of outside states in the 2016 US presidential election, and asks how western democracy can be kept healthy.Anne Applebaum has studied the ways in which democracy can arise like a phoenix from the ashes of authoritarianism. As the author of Red Famine: Stalin's War On Ukraine, and a professor at the LSE, she has analysed the reasons why democracy flourished in Poland and Ukraine after 1989, and suggests reasons why the 2012 Arab Spring has not yet had the same results. But as a journalist for the Washington Post she is all too aware of attacks on democracy today, both in the former Soviet bloc and in America. She argues that the onus is on us to save our own systems.Producer: Hannah Sander.

The Italian physicist Carlo Rovelli delves into the meaning of time. He tells Andrew Marr how we live in a timeless world but have evolved to perceive time's flow.The astrophysicist Carole Mundell is interested in the extragalactic. Her studies of the universe beyond our Milky Way help expand knowledge of cosmic black holes and explain powerful explosions in space.Space travel is the new frontier, but exactly 250 years ago the Endeavour set sail from Plymouth seeking to test the limits of scientific understanding. An exhibition at the British Library, curated by Laura Walker, tells the story of Captain Cook's world-changing voyages and their studies into the skies, seas and lands beyond our shores.And the marine biologist Helen Scales is more interested in exploring the world beneath the oceans. Her latest book marvels at the wonders of fish, from centuries-old giants to tiny restless travellers moving in shoals across our globe.Producer: Katy Hickman.

Tom Sutcliffe discusses free will and fate; dreams and reality. Jesmyn Ward's prize-winning novel Sing, Unburied, Sing, set in the American South, is haunted by the ghosts of the past. Ward writes of incarceration and freedom, and the strength - and weakness - of family bonds.For his latest ballet, choreographer Kim Brandstrup has taken inspiration from Calderon's 17th century Spanish play Life is a Dream, in which a dire prophecy leads a King to imprison his son. Brandstrup uses contemporary dance to explore where dreams end and reality begins, but also to express wonder at life itself.How to live well is at the centre of Edith Hall's self-help book based on the teachings of Aristotle. She examines the ancient Greek philosopher's ideas on how self-knowledge, responsibility and love could help us forge a more meaningful life. And the philosopher John Gray continues his exploration of what it is to be human in his new work, Seven Types of Atheism.Producer: Katy Hickman.

Fifty years after radicals took to the streets of Paris and stormed campuses across the Western World, Andrew Marr unpicks the legacy of 1968.Historian Richard Vinen finds waves of protest across the western world in his book The Long '68: Radical Protest and Its Enemies. Some movements were genuinely revolutionary, such as the ten million French workers whose strike nearly toppled the government. But on American university campuses and in British art schools, protests took the forms of civil rights marches and feminist collectives, whose narratives changed the way we think today.In Paris, left-wing students armed with works of philosophy took on the police and the state. But Paris was still coming to terms with its Nazi occupation, explains Agnès Poirier. Her new book follows the artists and writers of the 40s and 50s, from Simone de Beauvoir and Jean-Paul Sartre to Miles Davis and James Baldwin, as a new generation helped France regain its reputation for art, passion and political action.Not only left-wing radicals were inspired by the events of that year. In 1968 philosopher Roger Scruton was holed up in a Paris bedroom studying while rioters smashed windows outside. Scruton was horrified by the chaos and destruction, and turned his back on the left-wing politics of his childhood. He became part of a generation of new conservatives who sought to preserve the past rather than fight for an unknown future.Today France is facing new waves of strikes, with railway workers bringing the transport system to a halt and Emmanuel Macron pushing through sweeping reforms to social security. Sophie Pedder, Paris bureau chief for The Economist and author or a new biography of Macron, asks what France in 2018 owes to the events of 1968.Producer: Hannah Sander.

Facebook co-founder Chris Hughes makes a case for cash handouts to the poor. He tells Andrew Marr that having become exceptionally wealthy he is looking for the most efficient way to give something back to society, and a Universal Basic Income is among his ideas.But the Oxford academic Ian Goldin argues that UBI is an intellectual sticking plaster. He suggests targeted benefits, better taxation and philanthropy may be the answers to today's growing inequality and the prospect of mass job losses due to automation.Caroline Slocock was the first female Private Secretary at No.10, employed by Prime Minister Margaret Thatcher. She looks back at the last years of Thatcher's time in office, and Thatcher's vision of a smaller state and individual responsibility.Margaret Thatcher used the parable of the Good Samaritan to argue her case, suggesting that the voluntary actions of a wealthy Samaritan trumped the collective action of the state. Nick Spencer, Research Director at the public theology think tank Theos, explores how this parable has been hijacked for political ends from both the left and the right.Producers: Katy Hickman and Hannah Sander.

Amol Rajan discusses faith and doubt. Religion is a recurrent theme in Naomi Alderman's novels. Her first book, Disobedience, explored a Jewish girl's split with orthodox religion, while in Liar's Gospel she told multiple stories of Jesus through the eyes of those around him.Obedience was a virtue for the nuns of sixteenth-century Italy, but the music they wrote and sang was far less virtuous. Music professor and performer Laurie Stras has unearthed sensual and experimental works by nuns including the daughter of Lucrezia Borgia. And while many flocked to the nunneries to hear these women perform, others accused them of irreligious vanity.Historian and Anglican priest Malcolm Guite tells the life of Samuel Taylor Coleridge and finds religious imagery permeating Coleridge's most famous work, The Rime of the Ancient Mariner.And the writer and former Bishop of Edinburgh, Richard Holloway, asks how spiritual belief can help us face our mortality, in his new book Waiting for the Last Bus.Producer: Katy Hickman.

Sue Black spends much of her time with dead bodies. As one of the world's leading forensic anthropologists she has encountered death in many forms, leading British expeditions to Kosovo and to Thailand following the Boxing Day Tsunami. She tells Andrew Marr what ancient cadavers and recent corpses can teach us about mortality.Medieval depictions of death and injury don't shy away from the grotesque, says art historian Jack Hartnell. The mutilated bodies of saints and martyrs were often on display in medieval buildings, but these blood-spattered images were meant to inspire hope and faith.A devastating loss divides a couple in award-winning novelist Kit de Waal's new book, The Trick to Time. As an expert in fostering and adoption, she has also helped both adults and children cope with the lifelong impact of tragedy.A courageous child sits at the heart of composer Mark-Anthony Turnage's latest opera, Coraline, a dark fantasy based on Neil Gaiman's tale. The heroic Coraline finds a magical world in her attic and steps inside. But this world's Other Mother is not to be trusted and Coraline must fight to restore her real family.Producer: Hannah Sander.

We are drawn to wildness and disorder, argues historian Bettany Hughes. She tells Andrew Marr about the attraction of Bacchus, the god of wine and fertility, and the subject of a new BBC Four documentary. Bacchus (also known as Dionysus) has been a symbol of excess ever since Roman maidens fled to the woods and drank wine in his name. Hughes follows the Bacchic cult through history, and argues that chaos has been as important to civilisation as reason and restraint.The wood - scene of so many Bacchic revelries - comes to life in nature writer John Lewis-Stempel's new account, The Wood: The Life and Times of Cockshutt Wood. Through poetry, folklore and his own observations he asks what it is that draws us to magical spaces.Today we revel in feelings of joy and wonder, but feelings themselves are a surprisingly modern invention, says cultural historian Rachel Hewitt. She looks back at the 1790s, the decade when men and women of learning first began to take emotions seriously. Hewitt explains how an Enlightenment interest in reason led us to explore our own chaotic moods.There are Bacchic scenes in the music of Debussy, as biographer Stephen Walsh shows in a new study of the French composer. Away from his piano Debussy had to battle professional vendettas, but in pieces such as Prelude to the Afternoon of a Faun, Debussy created a world of rich woodland scenes and musical intoxication.Producer: Hannah Sander.

At the Free Thinking Festival at Sage Gateshead Lionel Shriver discusses her new collection of short stories Property with presenter Kirsty Wark.While Lionel Shriver explores our relationship with objects and places, and asks what the increasing accumulation of things may be doing to the soul, the sociologist Bev Skeggs explores how we are being bought and sold in the digital sphere. She also counts the cost of the monetisation of human relations and highlights communities in the North of England who are bucking this trend.The economist Linda Yueh looks back to the thinkers of the past from Adam Smith to Milton Friedman, to show the importance of understanding the ideas that underpin the world of finance. And the poet Sean O'Brien armed with 'paper and a clock' explores the history of Europe in his latest collection and argues that Great Britain's future will be shaped by what we remember and what we forget of our shared past.Producer: Katy Hickman.

What is art - and why do we need it? Fifty years ago the landmark BBC Two series Civilisation set out to answer this question. Now historians Mary Beard, Simon Schama and David Olusoga take on this challenge of defining human civilisation through art, in a bold update renamed Civilisations. Mary Beard tells Andrew Marr how humans have chosen to depict themselves, from enormous pre-historic heads in Mexico to lustful paintings meant for male eyes. She unpicks the bloody battle between religion and art, and declares that "one man's art is another's barbarity".But should art make us recoil? Simon Schama explores our urge to destroy the images we dislike, and finds that hatred and destruction have followed art through the centuries. This clash of religions and cultures has enriched art, argues David Olusoga. He sees culture on the frontline as empires expanded and a battle took place to define what art could be.This spring the artist Tacita Dean offers her own account of art's value and meaning as she unveils three exhibitions at once: exploring landscapes at the Royal Academy, portraits at the National Portrait Gallery and still life at the National Gallery. Moving between film and painted images, she challenges our idea of what art looks like.Producer: Hannah Sander.