As in three previous hearings, Saddam Hussein was the last to enter the courtroom on Tuesday when the trial resumed.
As well as his usual Quran, he carried files and papers, after his protests to the judge on Monday that he had been forced to take notes on his hands.
"Good morning to all those who respect the law," the deposed president said, greeting his co-defendants.
"Today we are beginning our fourth hearing," announced presiding judge Rizkar Mohammed Amin in the heavily defended Baghdad courtroom of the Iraqi High Tribunal.
The court cut the audio feed to journalists, allowing a woman witness to speak without her voice being identified.
A US official close to the proceedings said earlier that witnesses would on Tuesday give testimony without their faces appearing on delayed television footage and with their voices disguised for security reasons.
"Good morning to all those who respect the law"
Former Iraqi president
Mesmerising the world with chilling accounts of torture from witnesses and angry tirades from Saddam blasting the legality of the proceedings, the Iraqi courtroom drama has been called the trial of the century by local media.
Saddam, overthrown by invading US-led troops in 2003, is on trial with seven others for the massacre of 148 people from the Shia village of Dujail in 1982.
The eight defendants, who have pleaded not guilty, face the death penalty by hanging if convicted.
Saddam said he was unafraid of the death penalty after the court was subjected to tearful accounts of murder and torture, including the use of a meat grinder and electric shocks, from one witness on Monday.
"I am not afraid of being executed," Saddam said, after an earlier outburst in which he shouted: "Long live Iraq!"
Witness Ahmad Muhammad
Hassim al-Dujaili cries in court
Commentators have accused the former president of trying to hijack the trial with his repeated tirades, mirrored by similar interjections from his co-defendant and half-brother Barzan al-Tikriti, who is suffering from cancer.
Among the other defendants are Taha Yassin Ramadan, Saddam's former vice-president, and Awad Ahmad al-Bandar, head judge of the revolutionary court.
The process began with a brief opening on 19 October, followed by a 40-day delay and a two-hour session on 28 November before a week-long adjournment.
The trial has been plagued by a range of problems since its inception, most notably serious security issues.
Iraqi security forces said on Sunday that they had foiled a plot by fighters to fire rockets at the court building.