Short answers, pulled from the story.
Operation Crusader was a British Eighth Army offensive against Axis forces in North Africa, fought from the 18th of November to the 30th of December 1941. Its aim was to bypass the Axis frontier defences, destroy the Axis armour near Tobruk, lift the siege of that port and retake Cyrenaica.
Operation Crusader began before dawn on the 18th of November 1941, when the Eighth Army crossed the Libyan border near Fort Maddalena in a surprise attack. Rommel was not in Africa when the attack started, having been convinced by a deception plan that no assault was imminent.
Generalleutnant Erwin Rommel commanded the Axis forces during Operation Crusader, leading Panzergruppe Afrika, which he had commanded since July 1941. The Deutsches Afrika Korps within it was led by Lieutenant-General Ludwig Crüwell.
The Eighth Army lost 530 tanks between the 18th and the 22nd of November 1941, the first four days of Operation Crusader. Axis forces lost about 100 tanks over the same period.
Lieutenant-General Alan Cunningham was replaced after he grew alarmed by British tank losses and, on the 23rd of November 1941, asked Auchinleck whether the operation should continue. Auchinleck ordered him to press on regardless of losses, then had him relieved on the advice of Air Marshal Tedder and replaced with Major-General Neil Ritchie.
Operation Crusader ended with Axis forces withdrawn to El Agheila by the 30th of December 1941, after the siege of Tobruk was lifted on the 27th of November. The Eighth Army then captured Bardia on the 2nd of January 1942, Sollum on the 12th of January and the Halfaya position on the 17th of January, taking about 13,800 prisoners. Rommel's surprise attack from El Agheila on the 21st of January 1942 then drove the Eighth Army back to Gazala.