Think Tanks are now firmly part of the language of contemporary politics.
In two series for The Westminster Hour, Dennis Sewell reported on their growth and how they influence politicians in the United States, Britain and the European Union.
Think tanks came into the language for the first time after World War 2, meaning research institutes or other bodies providing advice and ideas on national or commercial problems.
In George W. Bush's America think tanks on the right have a big role. Dennis Sewell went to meet them - and their Democrat rivals - for the first series of In the Think Tanks, originally broadcast in late 2002.
And he asks what lessons Britain's smaller, and less wealthy, think tanks can learn from their American cousins.
In his opening report, Dennis Sewell speaks to 'policy wonks' on the American right who are driving the agenda of George Bush.
Click here to Sewell in America - Part One
In his second piece, Dennis talks to their rivals among Washington's left of centre policy wonks - which takes him on a visit to America's most venerable think tank - the influential Brookings Institution.
The Brookings Institution in Washington DC
Click here to Sewell in America - Part Two
In his final report, Dennis Sewell asks whether British think tanks will ever enjoy the Sherman-like status and firepower of America's tanks.
Click here to Sewell in America - Part Three
In a second series on The Westminster Hour in January and February 2004 Dennis Sewell investigates think tanks serving Europe.
He turns his attention to the think tanks developing ideas about the future of the European Union and its institutions.
Some are firmly committed to a vision of a federalist European Union, others far less sure. We talk to them.
Click here to listen to Sewell in Europe - Part One
Click here to listen to Sewell in Europe - Part Two
Click here to listen to Sewell in Europe - Part Three