The years between 1890 and 1920 probably saw more profound changes in the US Army than any other comparable period. In little more than a quarter-century the Army was transformed from a small blue-clad force which fought with single-shot rifles, colours flying, against disturbers of America's internal peace, into a mighty host of men dressed in dirt-coloured combat uniforms, using automatic weapons, tanks and aircraft against its country's enemies on fields across the world. These changes reflected – indeed, in many ways spearheaded – the transformation of America herself, from an inward-looking third-class nation into a powerful and confident world power.