Age: Approaching 60.
Who is she? Bosnian Serb vicepresident. Deputy to Radovan Karadzic, who is now keeping a lower profile in Bosnian Serb affairs.
Why's she in the news? Has been appointed to represent the Bosnian Serbs in dealings with the international community.
What's she like? Formidable.
Nicknamed the "Iron Lady of the Bosnian Serbs". Known for virulent outbursts and no nonsense nationalism, she is regarded as from the Karadzic school of thought.
A biologist by profession, formerly a professor in Sarajevo university, she joined Karadzic's Serb Democratic Party and was elected to the Bosnian collective presidency (1991).
Liked to warn Bosnia's Muslims, before war broke out, that "it is pleasant to live with Serbs but difficult to wage war on them".
During the 43 months of war she took the Serb line of secession from Bosnia, promoting the ideal of the Greater Serb state.
She once famously froze out Serbian President Slobodan Milosevic, who was endeavouring to get reluctant Bosnian Serbs to sign a peace agreement, despite his being their main patron (1993).
With the signing of the Dayton peace agreement (late 1995) she disappeared politically, to re emerge last weekend as Karadzic's protege.
Isn't Karadzic wanted by the UN? Both he and Bosnian Serb military commander Gen Ratko Mladic have been indicted on genocide charges by the International Criminal Tribunal in the Hague.
Biljana has confirmed a planned referendum of support for the two.
She stated that Karadzic would not resign as Bosnian Serb leader, that he was still "president" of the Serb entity in Bosnia.
However: "If the people of Republika Srpska (Bosnian Serbs) wish to place a little `x' in a box saying that they think Dr Karadzic is a wonderful person that's entirely their affair," said Colum Murphy, spokesman for international mediator Carl Bildt.
"What legal merit it has is another matter."
Last word: Goes to Colum Murphy.
Plavsic, he said, was "an extreme hardliner . . . and an extreme ultranationalist".
Karadzic, he added, was "quite clearly seeking to retain his influence" in Serb affairs.