Following are some questions and answers about the Iraqi tribunal trying Saddam Hussein and seven others.

Who is trying Saddam?
Saddam and his co-defendants are being tried before what was originally called the Iraqi Special Tribunal, established in December 2003 by US-led occupation authorities. It became known as the Iraqi High Tribunal in October and consists of two trial chambers with five judges in each.

Who brought the charges?
The tribunal has 20 investigative judges, led by a chief investigator, who gather evidence against suspects. Once an investigator has gathered evidence, including depositions from witnesses, he presents his case to the chief investigator.

If he gives the go-ahead, the case file is presented to the trial judges who decide whether there is enough evidence to proceed. In Saddam's case, the evidence about the killing of more than 140 Shia men from Dujail village, north of Baghdad, after a 1982 attempt on the former president's life, was gathered by chief investigative judge Raed al-Juhi.

The case against Saddam and the others was presented in court by the chief prosecutor.

Who is defending Saddam and the others?
Saddam is being defended by a small team of lawyers led by Khalil al-Dulaimi, an Iraqi with little experience in major criminal cases.

The other defendants are represented by an array of Iraqi lawyers.

Ramsey Clark, a former US attorney-general and Najib al-Nuaimi, a Qatari former justice minister, joined the defence at the last minute as international observers.

If found guilty, can Saddam appeal?
Yes. The tribunal has a nine-member appeals chamber. According to the tribunal statutes, any sentence handed down by the trial judges must be carried out within 30 days of all appeals being exhausted. The specific charges in the Dujail case carry a maximum sentence of death, which is by hanging in Iraq.

Will Saddam take the witness stand?
Saddam can be called to give evidence in his own defence, but under Iraqi judicial procedures it is the tribunal judges who conduct the examination. Lawyers for the prosecution and the defence can address questions to witnesses only via the judges.

Will Saddam see the witnesses?
The marble-lined courtroom provides for a screen to be drawn to protect the anonymity of some witnesses. Observers view the court from behind security glass. Television coverage is transmitted with at least a 30-minute delay.

How long will the Dujail trial last?
Some officials say the trial may take several more months. The appeals process may also last months.