A method of forming a three-dimensional object, comprising: (a) providing an epoxy dual cure resin; (b) forming a three-dimensional intermediate from said resin, where said intermediate has the shape of, or a shape to be imparted to, said three-dimensional object, wherein said resin is solidified by exposure to light, and wherein said forming step is carried out by either bottom-up three-dimensional fabrication between a carrier and a build surface or top-down three-dimensional fabrication between a carrier and a fill level, the fill level optionally defined by a build surface; then (c) optionally washing the three-dimensional intermediate, and (d) heating and/or microwave irradiating said three-dimensional intermediate sufficiently to further cure said resin and form said three-dimensional object; wherein said epoxy dual cure resin comprises: (i) a photoinitiator; (ii) monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light; (iii) optionally, a light absorbing pigment or dye; (iv) an epoxy resin; (v) an organic hardener co-polymerizable with said epoxy resin; (vi) optionally but preferably a dual reactive compound having substituted thereon a first reactive group reactive with said monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light, and a second reactive group reactive with said epoxy resin ( e.g., an epoxy acrylate); (vii) optionally a diluent; (viii) optionally a filler; and (ix) optionally, a co-monomer and/or a co-prepolymer. (a) providing an epoxy dual cure resin; (b) forming a three-dimensional intermediate from said resin, where said intermediate has the shape of, or a shape to be imparted to, said three-dimensional object, wherein said resin is solidified by exposure to light, and wherein said forming step is carried out by either bottom-up three-dimensional fabrication between a carrier and a build surface or top-down three-dimensional fabrication between a carrier and a fill level, the fill level optionally defined by a build surface; then (c) optionally washing the three-dimensional intermediate, and (d) heating and/or microwave irradiating said three-dimensional intermediate sufficiently to further cure said resin and form said three-dimensional object; wherein said epoxy dual cure resin comprises: (i) a photoinitiator; (ii) monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light; (iii) optionally, a light absorbing pigment or dye; (iv) an epoxy resin; (v) an organic hardener co-polymerizable with said epoxy resin; (vi) optionally but preferably a dual reactive compound having substituted thereon a first reactive group reactive with said monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light, and a second reactive group reactive with said epoxy resin ( e.g., an epoxy acrylate); (vii) optionally a diluent; (viii) optionally a filler; and (ix) optionally, a co-monomer and/or a co-prepolymer. (i) a photoinitiator; (ii) monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light; (iii) optionally, a light absorbing pigment or dye; (iv) an epoxy resin; (v) an organic hardener co-polymerizable with said epoxy resin; (vi) optionally but preferably a dual reactive compound having substituted thereon a first reactive group reactive with said monomers and/or prepolymers that are polymerizable by exposure to actinic radiation or light, and a second reactive group reactive with said epoxy resin ( e.g., an epoxy acrylate); (vii) optionally a diluent; (viii) optionally a filler; and (ix) optionally, a co-monomer and/or a co-prepolymer. <EOS>