Transparency is apparently the opposite of secrecy, but is it really a panacea?
BBC Radio 4
Is secrecy within the family harmful, or can it offer a necessary form of protection?
Tracing the development of the 'state secret', with a look at newly disclosed MI5 files.
A look at the purpose and power of secret objects and knowledge in different religions.
In the Middle Ages it was thought alchemy could unravel the secrets of nature.