Short answers, pulled from the story.
The Ba'ath Party took power through the 17th of July Revolution, a coup that began in the early hours of the 17th of July 1968. Military units and civilian Ba'athists seized key government buildings, cut telephone lines at 03:00, and positioned tanks in front of the Presidential Palace. President Abdul Rahman Arif surrendered and was flown to London. The coup succeeded without a single death.
Iraq invaded Kuwait on the 2nd of August 1990 primarily due to economic pressure: Kuwait and the United Arab Emirates were violating OPEC oil quotas, driving international oil prices down to US$13.67 per barrel by 1990 and costing Iraq an estimated one billion dollars in lost revenue. Kuwait also held Iraqi war debts that Iraq could not repay after the costly Iran-Iraq War.
By 1988, at the end of the Iran-Iraq War, Iraq fielded the fourth-largest army in the world, with 955,000 standing soldiers, 650,000 paramilitary forces, 4,500 tanks, 484 combat aircraft, and 232 combat helicopters. At the start of Ba'athist rule in 1967, the army had consisted of just 50,000 men.
The Iran-Iraq War, which lasted from 1980 to 1988, cost the Iraqi government 226 billion dollars and left a foreign debt estimated at 80-100 billion dollars. Oil export revenue fell from $26.1 billion in 1980 to $10.4 billion in 1981 after Iran bombed Iraq's oil facilities. Iraq began the war with monetary reserves of $35 billion; by the war's end, those reserves were depleted.
The Return to Faith Campaign, launched in 1993 and supervised by Izzat Ibrahim al-Douri, was a policy shift by the Ba'athist regime to promote Islamic observance in Iraqi society. It introduced Quranic studies into school curricula at all levels, established a religious radio station called al-Quran al-Karim Radio, incorporated sharia aspects into the judicial system, and added new criminal penalties including death for prostitution.
Saddam Hussein was executed on the 30th of December 2006. He was convicted by the Iraqi Special Tribunal for crimes against humanity related to the 1982 Dujail massacre, in which the Iraqi government killed Shia rebels. He had been captured by American troops in December 2003 and tried from 2005 to 2006.