In the spring of 1809, the Austrian army, buoyant and full of new-found patriotic fervor, rolled across the frontier with Bavaria. The time had come to exact revenge for the humiliating defeat suffered at Austerlitz. Napoleon was not in the front line when Austria had launched its campaign - and the French and their German allies blundered backwards and forwards across the Bavarian countryside. But, with the appearance of Napoleon, Archduke Charles lost the initiative, and ten days later, harassed by ceaseless rain, the Austrians were streaming back from the Abens river with Napoleon in hot pursuit. This volume covers the various clashes of this significant campaign, drawing upon previously unpublished Austrian primary sources.