British Assessment of US Army in Sicily (1943)

The particular features of U.S. troops, their equipment, extraordinary mobility, and general artillery methods, require special study if they are to be employed to the best advantage together with, and alongside, British troops in an Allied operation. It cannot be assumed that the armies of both Nations will fulfill similar tasks equally well: each has its peculiar characteristics suiting it, on the one hand, for wide and very speedy manoeuvre across difficult country, great elasticity and powers of improvisation, and extremely rapid concentration of fire power; and, on the other hand, for dogged fighting, resolute attack against prepared positions, stubborn defence, and the maintenance of close contact.

Source: Notes on the Planning and Assault Phases of the Sicilian Campaign, Combined Operations Headquarters, London, October 1943.