1/5 Professor Jeremy Black considers the primary military function of castles.
Rana Mitter with historians Richard J Evans, Jane Caplan and David Cesarani.
2/5 Nicola Coldstream explores the careers of two master masons.
With Tom Stoppard's play The Hard Problem, plus musician and neuroscientist Daniel Levitin
3/5 Benjamin Wild recounts the siege of Kenilworth castle - the longest in English history.
Including Joyce Carol Oates's new novel, the film Selma and the play Jefferson's Garden.
4/5 Prof Roberta Gilchrist discusses the place of women in the history of British castles.
Ian McMillan's guests include Neneh Cherry, David Constantine and April de Angelis.
5/5 Writer Ken Worpole reflects on the grim forts and defences of the east coast of Britain.
Tom Service meets pianist Kirill Gerstein and profiles harpsichordist Ralph Kirkpatrick.