Operation Husky, the Anglo-American amphibious landings on Sicily in July 1943 were the proving ground for all subsequent Allied amphibious operations including Salerno, Anzio, and D-Day in Normandy. Husky's strategic objective was to knock Italy out of the war, a mission that ultimately proved successful. But it also demonstrated the growing ability of Britain and the United States to conduct extremely complex combined-arms attacks involving not only amphibious landings, but also airborne assaults. It was in many ways the precursor of all modern joint operations through the recent wars in Iraq and Afghanistan as two different armies and navies with their own methods of command and control adjusted their practices to conduct a harmonious operation. This stood in stark contrast to the increasingly dysfunctional German-Italian alliance which finally broke down on Sicily.
Not only did the Sicily operation represent a watershed in tactical development of combined arms tactics, it was also an important test for future Allied joint operations. Senior British commanders left the North African theater with a jaundiced and dismissive view of the combat capabilities of the inexperienced US Army after the debacle at Kasserine Pass in Tunisia in February 1943. Sicily was a demonstration that the US Army had rapidly learned its lessons and was now capable of fighting as a co-equal of the British Army.
The Sicily campaign contained a measure of high drama as Patton took the reins of the Seventh US Army and bent the rules of the theater commander in a bold race to take Palermo on the northern Sicilian coast. Patton was determined to prove the ability of the US Army after Kasserine in the hands of a skilled tactical commander. When stiff German resistance halted Montgomery's main assault to Messina through the mountains, Patton was posed to be the first to reach the key Sicilian port and end the campaign.
The Sicily campaign contains a fair amount of controversy as well including the disastrous problems with early airborne assaults and the Allied failure to seal the straits of Messina, allowing the Germans to withdraw many of their best forces.