This report is a summary of the work accomplished within the Dynamic add-on armour project during the last three years. The intention has been to develop the knowledge of the possibilities and limitations of dynamic add-on armour concepts with emphasis on protection for lightweight vehicles against simpler SC-warheads and medium calibre long rod projectiles as those threats is judged to constitute a future severe threat in international operations. There are many effective armour concepts available for tanks to defeat the type of SCwarhead considered. The base armour at lightweight vehicles though is very limited why the available armour concepts have to be modified for this application. It is harder to find weight efficient armour concepts to defeat long rod projectiles as they are much more robust and difficult to disturb than SC-warheads. The requirements on the armour components to achieve an effective disturbance on a SC-jet or a long rod projectile are partly different. For example the plates in armour against shaped charges have to react very fast while the plates in armour against projectiles ought to have a moderate velocity to achieve a long interaction time. It is though desirable that one and the same armour modulus could defeat both simple SC-warheads and projectiles. Our judgment is that dynamic add-on armours, i.e. armour modulus composed of nonstationary armour components mounted on the vehicle as a complement to the base armour, are necessary to achieve the desired protection on lightweight vehicles. The studies indicate that combined explosive-inert reactive armour, having a short enough reaction time to defeat all of the SC-jet, is an interesting armour concept for lightweight vehicles against simple man-portable SC-warheads. The studies also resulted in knowledge on what type of armour components to use to achieve effective protection against projectiles. Even the most effective add-on armours require though a relatively thick base armour to defeat the residual parts of a fragmented projectile. The results constitute a base for continuing studies in this area.