The trial, to restart after a five-week recess, has to date focused only on the killing of more than 140 Shia Muslims in Dujail in 1982.
If convicted on the first charge, and if the sentence is upheld, Saddam would face death by hanging and might never be judged for other crimes of which he is accused.
At an initial court hearing on 19 October, he pleaded not guilty to charges of crimes against humanity related to the 1982 killings.
Daily hearings are scheduled until Thursday, when prosecution witnesses are likely to be heard.
Meanwhile, an American civil rights lawyer and a former justice minister of Qatar said they were heading to Baghdad to help defend Saddam and ensure that he gets a fair trial.
Former U.S. Attorney General Ramsey Clark, a former US Attorney-General, and Najeeb al-Nauimi, former justice minister in Qatar, told Reuters in Amman that they were on their way to the Iraqi capital and would join Khalil Dulaimi, the chief defence lawyer when proceedings resumed.
Saddam, whose name in Arabic means "he who confronts", cut a defiant figure in court last month, questioning the trial's legitimacy, refusing to state his name for the judge and tussling with guards.
The former leader's habit of videotaping all his orders to ensure that they were carried out has backfired against him, according to an unnamed source close to the investigation. "Everything was filmed," he said.
The following are some of the other alleged crimes for which Saddam might be formally charged at a later stage:
The gassing of Kurds in Halabja, northern Iraq took place during the infamous Anfal campaign that included a policy of demolishing homes, evictions and separating men from their families.
More than 5000 people died in in the attack on Halabja on 16 March 1988.
Between February and November 1988, the Anfal campaign declared 95% of property in the north off-limits and 180,000 people are reported to have disappeared.
Many women and children died from a lack of food and medical attention, and Kurdish fighters were allegedly executed in the deserts of western and southwest Iraq.
2. Iran-Iraq war
The United Nations has blamed Saddam's Iraq for starting the 1980-1988 conflict against neighbouring Iran, although his government argued that the war was provoked by cross-border shelling by the Iranians.
About a million people were estimated to have been killed in the eight-year war before Ayat Allah Khomeini, the Iranian leader, accepted a UN-sponsored ceasefire.
Iran's judiciary says it has finalised charges of genocide and using chemical weapons that it hopes will be levelled against Saddam.
3. Invasion of Kuwait
The Iraqi leader's tanks rolled into Kuwait on 2 August 1990, annexing the oil-rich Gulf state as Iraq's 19th province and its historical right.
US-led multinational forces drove Iraqi troops out of the emirate after a seven-month occupation during the Gulf war.
In September this year, Kuwaiti authorities said they would also seek a trial and the death penalty for Saddam's crimes against the emirate.
After Iraq's defeat in the first Gulf war, coalition forces encouraged soldiers and civilians to rise up against Saddam in the south, but tens of thousands were subsequently massacred.
Brutal crackdowns took place around the cities of Najaf and Karbala.
4. Kurdish massacre
Iraqi forces under Saddam are accused of the massacre in 1983 of the Kurdish tribe of Mulla Mustafa Barzani, the founding father of Iraqi Kurdistan who died in March 1979.
Saddam's government allegedly rounded up about 8000 men from the tribe in northern Iraq, took them into the desert and executed them.
In 1980, another tribe of Faylee Kurds were expelled from Iraq to Iran, while some were said to have been massacred in northern Iraq.
5. Widespread rights abuses
The former Iraqi president is also alleged to have systematically tortured, executed or intimidated all Iraqis who opposed his government, whether Shia, Sunni Arab, Kurd or Turkmen.