The role of the special adviser is one of the most controversial issues in British politics, with this unelected subdivision of the political class having multiplied in both number and influence since the advent of New Labour.

But there is nothing new in the idea of leaders bringing in outsiders to advise on particular areas of policy or party politics, and this first in-depth study of special advisers brings an historical as well as an analytical perspective to a hot topic.

John Maynard Keynes, Lord Cherwell ('The Prof'), William Beveridge, Balogh and Kaldor, Alan Walters, Alastair Campbell, Jo Moore - the list of Whitehall outsiders who have left a footprint on British political history is considerable.

But has the proliferation of special advisers under Blair really been harmful to the democratic process? People who Live in the Dark - the book takes its title from Clare Short's exasperated assessment of spin doctors - examines the history and the issues.

'Special advisers have hit the headlines in the Blair years in a spectacular and sustained fashion. But where did these hybrid creatures - part politician, part civil servant - come from? Like all significant mutations, they had a long gestation. Andrew Blick has unravelled their history and their DNA like no other. Nobody who pretends to understand the way we are governed in the twenty-first century can be without this volume.' Peter Hennessy