Abstract: An in-fill wall system for use in building construction including substantially horizontal floors and ceilings held in substantially parallel relationship relative to each other by a plurality of substantially vertical support columns comprising a plurality of multi-layer panels secured between adjacent substantially vertical support columns, each multi-layer panel comprises an inner panel core including a pair of panel surfaces or sides at least the major portion of which is covered by an outer panel member wherein the lower edge portions of multi-layer panels are held in place by a substantially C or U-shaped channel or lower attached member affixed to the floor and held vertically in place by a pair of substantially L-shaped upper attachment members affixed to the ceiling on opposite sides of the upper edge portion of the multi-layer panels together with a pair of substantially L-shaped side attachment members affixed to a corresponding substantially vertical support column disposed on opposite sides of ea