He spent 12 years in prisons and psychiatric hospitals, was expelled from the Soviet Union in 1976, and has been at the forefront of opposition to Vladimir Putin. The indefatigable dissident Vladimir Bukovsky turns 70 this week. Bukovsky first exposed the use of psychiatry against Soviet political prisoners. His tenacious stand against an overwhelmingly powerful state infuriated the KGB and made him a hero in the west. Three decades later he stood against Vladimir Putin, a former KGB spy, in Russia‘s 2008 presidential election. (Predictably, they refused to let him run. Bukovsky was also detained at Moscow airport as he tried to leave the country.) Bukovsky’s account of his time in a succession of Soviet jails, gulags and lockups, To Build a Castle, is one of the 20th century’s great memoirs. A longtime Cambridge resident, and a friend of Alexander Litvinenko, Bukovsky has been a shining light in a darkening world.