Anders Breivik is not lawyer Geir Lippestad's first unpopular client.
In 2002 he represented a neo-Nazi who knifed to death a mixed-race teenager in Oslo.
The murder of Benjamin Hermansen - son of a black Ghanaian father and white Norwegian mother - sparked public outcry in Norway and tens of thousands of people marched against race crimes.
His decision to represent Ole Nicolai Kvisler put him in the national spotlight, and his reputation for helping brutal murderers receive a fair trial is set to be demonstrated again.
Mr Lippestad, 47, received a telephone call the morning after the massacre to ask if he would represent Breivik.
According to reports his first reaction was to say no. The killing spree received global attention, and the lawyer is a member of the Labour Party, whose youth camp was attacked on Utoya island.
But after a conversation with his wife he decided he should take the case on.
Mr Lippestad will be assisted in the trial by Vibeke Hein Baera, Tord Jordet and Odd Ivar Groen.
Breivik first appeared in court in Oslo on July 27 last year. Mr Lippestad said his client had wanted to revolutionise
Norway's society and had "confessed to the factual circumstances" of the atrocities but denied criminal responsibility.
He told Norwegian broadcaster NRK: "He wanted a change in society and, from his perspective, he needed to force through a revolution. He wished to attack society and the structure of society."
The lawyer has described Breivik as a "very cold" person who appeared to have no idea of the worldwide revulsion at his acts.
A psychiatric report presented to the Oslo district court on Tuesday backed up Breivik's own claim that he is sane, and contradicted an earlier assessment that declared him psychotic.
Meanwhile a number of groups have been created by Norwegians on Facebook to support Mr Lippestad's actions.
One user described him as "doing a great job with great dignity" while another said he showed "great wisdom, respect and humility for the job and the values of a democracy".
Mr Lippestad has admitted that the case is having a serious impact on his life.
He recently told French newspaper Le Monde: "I feel I have lost my soul in this case.
"I hope to get it back once it's over - and that it will be in the same condition as before."
He and his wife have a total of eight children, including several from previous relationships.