Russia's charismatic protest leader Alexei Navalny, who challenges pro-Kremlin mayor Sergei Sobyanin in Moscow's elections Sunday, has galvanised the opposition with lacerating attacks on President Vladimir Putin and the Russian elite.
Navalny, 37, is a new breed of Russian protest leader who wants to become a player in mainstream politics after building up a huge Internet following with sharply-written blogs and corruption exposes.
He emerged as the key figure in the mass opposition protests that rocked Russia in the winter of 2011-2012 ahead of Putin's return for a third Kremlin term last May.
In July he was sentenced to five years in jail in a controversial embezzlement case but then dramatically released a day later pending his appeal in a twist that stunned observers.
His sometimes volcanic rhetoric inspired supporters in a way never seen before in post-Soviet Russia, provocatively declaring at a rally in December 2011 that he could muster enough protestors to take the Kremlin.
He has boldly stated an ambition to become president in 2018 polls and "change the country", while jailing Putin and his allies, who he accuses of large-scale corruption.
Twice jailed briefly for administrative offences during the protests, he is no stranger to tough street talk and told a policeman who roughly arrested him last May that he would prosecute him afterwards.
It was Navalny who dreamt up the infectious slogan calling United Russia "the party of swindlers and thieves", which it has not managed to shake off.
But held back by the lack of coverage on state television, he has yet to make an impact in the regions beyond his Moscow powerbase and many Russians have no clue who he is.
In the Russian capital, 18 percent are expected to vote for him in the Moscow mayor election, according to a poll by the independent Levada Centre.
Navalny began his anti-corruption crusade in 2007, buying up shares in state-controlled companies and grilling management at their annual general meetings.
Realising the power of the Internet well before the Russian elite, he published reports alleging corruption and mass embezzlement at giant enterprises on his Rospil website (Rospil.info), which built up a loyal following.
Navalny makes astute use of the colloquial forms of the Russian language -- where plays on words are hugely popular -- in a way never dreamt of by any Kremlin official.
Seeking to present himself as an ordinary guy, Navalny lives with his wife Yulia -- who has become an increasingly visible presence at his side -- in a humdrum and otherwise unremarkable Moscow suburb called Maryino.
"Navalny is someone like you - he is not someone backed by oligarchs and bureaucrats," says his campaign literature for the mayoral elections.
"Let's change Russia, starting with Moscow."
Nevertheless, his views on ethnic relations trouble liberals, in particular in such a multi-cultural country like Russia which is home to an estimated 20 million Muslims.
He coined the slogan "it's time to stop feeding" Russia's volatile North Caucasus and has spoken at the ultra-right Russian Marches, behaviour that earlier led to his expulsion from the liberal Yabloko party.