Edward Davey has long been regarded within Liberal Democrat circles as a potential future leader.
Mr Davey designed the party's local income tax policy
Bright and personable, he is an expert on taxation and finance and was Sir Menzies Campbell's chief of staff.
But he is not particularly well known outside the party faithful, marking the Kingston and Surbiton MP out as a possible "one for the future".
Since his election in 1997 Mr Davey, 41, has held several briefs, including speaking on education and industry. He also drew up the party's local income tax policy.
In the last year, he has been closely associated with Sir Menzies' leadership, serving as his campaigns co-ordinator.
His links to the former leader could be seen as either a help or a hindrance at a time when the Lib Dems are searching for new direction, and an improvement in the opinion polls.
Mr Davey co-wrote the 2004 Orange Book, which stresses the benefits of the free market in tackling social problems.
If he had stood for the leadership, it would have been alongside other contributors on the right wing of the party, such as home affairs spokesman Nick Clegg and environment spokesman Chris Huhne.
Commentators predicted that Mr Davey might have difficulty marking out a distinctive bid in such crowded territory.
His decision not to stand did not come as a surprise, but Mr Davey's courage is hard to question.
He won a police commendation and a bravery award from the Royal Humane Society in 1994 after he rescued a woman who had fallen onto a railway line in the face of an oncoming train.
Mr Davey's parents died when he was a child, and he was brought up by grandparents.
He was head boy of Nottingham High School - formerly attended by Tory heavyweight Kenneth Clarke and Labour Cabinet ministers Geoff Hoon and Ed Balls.
He went to Oxford, where he gained a first-class degree in philosophy, politics and economics, before joining the Lib Dems as an adviser.
He went on to work as a management consultant until he became an MP in 1997, with a majority of just 56. This increased to 15,676 at the 2001 general election, but fell to 8,966 in 2005.
Mr Davey, whose hobbies include walking and supporting Notts County FC, is married and lives in his constituency.