HIGH PERFORMANCE, THERMALLY INSULATING MULTIPANE GLAZING STRUCTURE Multipane, insulating glazing structures having exceptional thermal insulation performance are provided. The novel multipane structures comprise two substantially parallel rigid glazing sheets spaced apart by an interior spacer of a low thermal conductivity, closed cell, foamed polymer. In a preferred embodiment, the glazing sheets are present in a four-pane structure filled with an inert gas and sealed with a gas-impermeable, continuous tape overlaying a curable, high modulus sealant. Methods for manufacturing the novel glazing structures are disclosed as well.