Critics say Baltasar Garzon has overstepped his authority
Rarely can a modern-day judge have stirred as much controversy as Spain's Baltasar Garzon.
To some he is a crusading hero, taking on dictators and terrorists on behalf of the world's oppressed.
To others he is a left-wing busybody obsessed with self-promotion.
While he was pursuing foreigners with questionable human rights records, the criticism directed at him was mainly just that - criticism.
But by delving into Spain's own murky past, he has provoked more strident opposition, and now faces trial, accused of over-reaching his judicial powers.
Mr Garzon came to worldwide attention in the late 1990s, when the former Chilean military ruler Augusto Pinochet was arrested in London on his initiative.
He was acting under Spain's principle of universal jurisdiction, which holds that some crimes are so grave that they can be tried anywhere regardless of where the offences were committed.
The most famous case was an attempt to extradite Gen Pinochet in 1998
Pinochet headed Chile's military regime from 1973-1990, when up to 30,000 people were killed or "disappeared" in the campaign against so-called left-wing insurgents.
Pinochet was arrested in the UK in 1998 and detained for 18 months while Spain's extradition request was considered. In the end, it was ruled he was too frail and he was allowed to go home.
Mr Garzon has also initiated other high-profile cases. In 2003 he compiled a 692-page indictment which called for the arrest of 35 men, including Osama Bin Laden, for their alleged membership of a terrorist group. That number was later increased to 41.
In 2005, 24 of them were put on trial in Madrid, in Europe's biggest trial of alleged al-Qaeda operatives.
Eighteen were found guilty of belonging to an al-Qaeda cell and sentenced to long prison terms.
Judge Garzon was also behind the trial in Spain of Argentine ex-naval officer Adolfo Scilingo, who was convicted of crimes against humanity and sentenced to 640 years in jail in April 2005.
Civil war taboo
Mr Garzon is one of six investigating judges for Spain's National Court which, like many other European countries, operates an inquisitorial system as opposed to the adversarial system used by the US and UK. It is thought he will be suspended as a result of the charges against him.
The investigating judge's role is to examine the cases assigned to him by the court, gathering evidence and evaluating whether the case should be brought to trial. He does not try the cases himself.
The judge did start his investigations closer to home.
The Franco era remains deeply divisive in Spain
He took on the semi-official GAL death squads which operated in Spain's Basque region in the early 1980s - leading to the jailing of former Socialist Interior Minister Jose Barrionuevo.
He has also been active in Madrid's crackdown on the Basque separatist group Eta and is reported to have been on the group's list of assassination targets.
But it was by attempting to prise the lid off Spain's Civil War and the subsequent rule of right-wing dictator General Francisco Franco that he really opened a can of worms.
The subject has long been taboo in Spain and is only now starting to be discussed.
In October 2008, Mr Garzon launched an unprecedented inquiry into the "crimes against humanity" of the Franco era, promising to investigate the disappearance of more than 100,000 people and ordering the excavation of mass graves.
For some, that overstepped the mark. Under heavy pressure, he withdrew the investigation.
A right-wing civil servants' union accused him of overreaching his judicial powers by breaching the official amnesty that drew a line under the Franco era in 1977. That complaint led to him being summonsed to answer questions before the Supreme Court.
He has also found himself in other difficulties.
He was investigated and cleared over allegations that he was improperly paid for teaching in New York while on sabbatical from his job in Madrid.
In February 2009 Spain's Justice Minister, Mariano Fernandez Bermejo, was forced to resign after going on a hunting trip with Mr Garzon. It followed accusations that he had tried to influence the judge's investigation into members of the opposition Popular Party - claims the minister denied.
But perhaps the biggest threat to Mr Garzon's fame is a move in Spain to curtail the principle of universal jurisdiction. The Spanish government says despite its lofty ideals it does not work, taking up a great deal of time and money but resulting in hardly any convictions.