This first of three volumes deals with all the artillery pieces of domestic, foreign and pre-war production used and in regular use by the Royal Italian Army in the Second World War. Each weapon is described with one or more colour profiles and an exhaustive sheet on the weapon's technique and characteristics. In the first volume, we will mainly deal with the guns inherited from the First World War, which were either domestically built or obtained as war booty, starting with the smallest calibres. In this volume, we will also present the first part of tractors used for this type of weapon.