The man accused of killing 77 people in bomb and gun attacks in Norway last July is due to take to the stand on the second day of his trial in Oslo.
Anders Behring Breivik will read out a prepared statement on Tuesday that will take about 30 minutes, his lawyer said.
He has admitted carrying out a car bombing in the capital before attacking a youth camp organised by the governing Labour party on the island of Utoeya.
However, he has pleaded not guilty to acts of terror and mass murder.
He said he had acted to protect Norway from multi-culturalism and Islam.
On Monday, prosecutors played harrowing recordings of the events and described the fate of each victim in detail.
Throughout the evidence Breivik remained emotionless, although he broke down when the court played a 12-minute anti-Islam video which he had posted online on the day of the carnage.
Breivik's lawyer, Geir Lippestad, later said that his client appeared to have cried over feelings that his attacks were "cruel but necessary... to save Europe from an ongoing war".
Breivik said he didn't recognise the court.
Mr Lippestad said he understood that victims' families were worried Breivik would use his trial as a pulpit.
"On the other hand - and this is important - he has a right to explain himself, a fundamental right under Norwegian law and a human right," he added.
Breivik detonated a bomb in a van parked outside government offices in Oslo on 22 July, killing eight people.
He then travelled to Utoeya where, dressed as a police officer, he shot dead a further 69 people.
Survivors and relatives of the victims gasped as previously unreleased footage was shown in court of people walking towards Breivik's parked van as it exploded outside the government block.
The court also heard Breivik's calls to police offering to give himself up.
"I have completed my operation and I want to surrender," Breivik said.
The 33-year-old Norwegian was found insane in one examination, while a second assessment made public last week found him mentally competent.
If the court decides he is criminally insane, he will be committed to psychiatric care; if he is judged to be mentally stable, he will be jailed if found guilty.
If jailed, he faces a sentence of 21 years which could be extended to keep him behind bars for the rest of his life.
Parts of the trial are being broadcast on television, although the court will not allow Breivik's testimony or that of his witnesses to be broadcast.
The courtroom has been specially built for the trial to accommodate more than 200 people.
Glass partitions have been put up to separate the victims and their families from Breivik.
The trial is expected to last for 10 weeks.