The report is based on an in-depth investigation by the US Senate, and was led by US Senator Dianne Feinstein, the chairwoman of the Senate Intelligence Committee.
Although many parts of the report are redacted, or have code names instead of countries, reporters and analysts have combined other information to glean details of which countries were actively supporting the US in its programme of secret prisons around the world, where torture was allegedly carried out by the CIA on a routine basis.
There were levels of cooperation in the programme. At the top were five countries with secret CIA-run prisons, including Afghanistan (four sites), Poland, Lithuania, Romania and Thailand.
Several other countries ran proxy prisons, where suspects were routinely tortured on behalf of, and with the active cooperation of the CIA, who often rendered the suspects into their custody.
They include Egypt, Syria, Libya, Pakistan, Jordan, Morocco, Gambia, Somalia, Uzbekistan, Ethiopia and Djibouti.
At the bottom of the list is a large group of countries which passively supported the suspected torture and known illegal rendition operations, including European countries such as Italy, Sweden, Finland, Denmark, Austria, Spain, Germany and the UK.
One of the most high profile cases was the 2003 abduction in Milan of Osama Mustafa Hassan Nasr, better known as Abu Omar, an Egyptian cleric who had been given asylum in the country.
In a joint operation by the CIA and the Italian secret service, he was then allegedly taken to the Aviano US air base in northeast Italy, flown to a US base in Germany, and on to Cairo, where he said he was tortured.
Despite opposition from Washington, an Italian court later convicted, in absentia, 22 CIA officers and a US Air Force pilot to at least five years in prison for the kidnapping. The agents have never been extradited, while the pilot was pardoned by Italian President Giorgio Napoletano.
Meanwhile, Abu Omar was last year sentenced by an Italian court to six years in prison for criminal association for international terror.
Prosecutors said he collaborated with 13 militants between 2000 and 2003 "with the aim of carrying out acts of terrorist violence in Italy and abroad."
Abu Omar's lawyer Carmelo Scambia said his client denied the charge and had only "adhered to a political-ideological course for his faith".