The Winter War was supposed to be a quick and easy conflict; instead it proved to be a bitter war that destroyed the international reputation of the Soviet Red Army. The diminutive Finnish force was desperately outnumbered by almost half a million Russian troops, but rather than sweeping across their neighbors, the Soviet troops stumbled blindly, constantly wrong-footed and then bloodied by their seemingly insignificant foe. Drawing on a wide range of sources, this study looks at three key battles, drawing a stark contrast between the poorly prepared Russian troops and the Finns, who made excellent use of terrain and innovative guerrilla tactics as they defended their homeland.