He is a former KGB colonel who has been accused of joking about rape and introducing homophobic legislation into Russian law.
The Russia of Vladimir Putin jails his political opponents, including members of the protest band Pussy Riot, and his first act as Russian Prime Minister in 1999 was to effectively initiate the Second Chechen War, which led to the death of thousands of civilians as cities and towns in the region were levelled.
Alex Salmond thinks there are "certain aspects" of the Russian president that are in fact admirable.
His comments about Mr Putin will no doubt raise eyebrows because of the current crisis in the Ukraine following the invasion of Crimea.
But away from the current eastern European situation, the Russian president has a history of controversial and outlandish behaviour.
He has come under criticism for failing to tackle the rising number of attacks on gay people in Russia, with reports that little or nothing is done by the police when incidents are reported.
The Sochi Winter Olympics in February this year were marred by widespread criticism of increasingly anti-gay legislation in a country where homophobia is said to be rampant.
A documentary made by the charity Stonewall and Vice magazine that was released online detailed how vigilantes hunt down gay teenagers and film their beatings.
Treatment included pouring urine on to the victims to "cleanse" them of their homosexuality.
When asked ahead of the Sochi games about how gay athletes might feel about coming to Russia given the country's homophobia, Mr Putin commented: "One can feel calm and at ease. Just leave kids alone, please."
There were calls for him to enter talks with Chechen separatists after the Beslan school hostage crisis in 2004, in which more than 380 people died.
Mr Putin said: "Why don't you meet Osama bin Laden, invite him to Brussels or to the White House and engage in talks, ask him what he wants and give it to him so he leaves you in peace?
"You find it possible to set some limitations in your dealings with these b*******, so why should we talk to people who are child-killers? No one has a moral right to tell us to talk to child-killers."
Speaking after the bombing of the Moscow Metro that same year, Mr Putin said: "Russia doesn't negotiate with terrorists. It destroys them."
Speaking to US president George W Bush at 2008's Nato Bucharest Summit, Mr Putin said Ukraine was "not even a state". He added: "What is Ukraine? Part of its territories is eastern Europe, but the greater part is a gift from us." Mr Putin has described Soviet Union's break-up as "the greatest geopolitical catastrophe of the century".
Commenting on sexual assault accusations against Israeli President Moshe Katsav in 2006, Mr Putin said he was a "mighty man" who had raped 10 women.
He said "He surprised us all - we all envy him!" A Kremlin spokesman claimed the real meaning of Mr Putin's comments was lost in translation.
In response to a tweet from Senator John McCain which said "Dear Vlad, The Arab Spring is coming to a neighbourhood near you," Mr Putin pointed out Mr McCain had fought in Vietnam.
He added: "He has enough blood of peaceful citizens on his hands. It must be impossible for him to live without these disgusting scenes anymore. Mr McCain was captured and they kept him not just in prison, but in a pit for several years. Anyone [in his place] would go nuts."
In 2007, a shirtless Mr Putin was pictured fishing in a Siberian river and with a rifle, images blatantly aimed at advertising his muscularity and his prowess as a leader.