A staple cartridge assembly, comprising: a cartridge body, comprising: a proximal end; a distal end; a deck; a longitudinal slot extending from said proximal end toward said distal end, wherein said longitudinal slot divides said deck into a first side and a second side; a plurality of staple cavities defined in said first side of said deck, wherein said staple cavities are arranged in: an inner staple cavity row extending along said longitudinal slot; an intermediate staple cavity row extending along said inner staple cavity row; and an outer staple cavity row extending along said intermediate staple cavity row, wherein a distal cluster of four staple cavities is constituted of a distal-most staple cavity in said inner row, a distal-most staple cavity in said intermediate row, a distal-most staple cavity in said outer row, and another staple cavity in one of said inner row, said intermediate row, and said outer row; a distal cluster of four staples removably stored in said distal cluster of staple cavities; and a distal cluster of four staple drivers configured to eject said distal cluster of staples from said distal cluster of staple cavities, wherein said four staple drivers move independently of one another; and characterized by: a tri-staple driver configured to eject three proximal staples from said cartridge body consisting of an inner staple from said inner row, an intermediate staple from said intermediate row, and an outer staple from said outer row, and wherein said tri-staple driver is positioned proximally with respect to said distal cluster of staple drivers. a cartridge body, comprising: a proximal end; a distal end; a deck; a longitudinal slot extending from said proximal end toward said distal end, wherein said longitudinal slot divides said deck into a first side and a second side; a plurality of staple cavities defined in said first side of said deck, wherein said staple cavities are arranged in: an inner staple cavity row extending along said longitudinal slot; an intermediate staple cavity row extending along said inner staple cavity row; and an outer staple cavity row extending along said intermediate staple cavity row, wherein a proximal end; a distal end; a deck; a longitudinal slot extending from said proximal end toward said distal end, wherein said longitudinal slot divides said deck into a first side and a second side; a plurality of staple cavities defined in said first side of said deck, wherein said staple cavities are arranged in: an inner staple cavity row extending along said longitudinal slot; an intermediate staple cavity row extending along said inner staple cavity row; and an outer staple cavity row extending along said intermediate staple cavity row, wherein an inner staple cavity row extending along said longitudinal slot; an intermediate staple cavity row extending along said inner staple cavity row; and an outer staple cavity row extending along said intermediate staple cavity row, wherein a distal cluster of four staple cavities is constituted of a distal-most staple cavity in said inner row, a distal-most staple cavity in said intermediate row, a distal-most staple cavity in said outer row, and another staple cavity in one of said inner row, said intermediate row, and said outer row; a distal cluster of four staples removably stored in said distal cluster of staple cavities; and a distal cluster of four staple drivers configured to eject said distal cluster of staples from said distal cluster of staple cavities, wherein said four staple drivers move independently of one another; and characterized by: a tri-staple driver configured to eject three proximal staples from said cartridge body consisting of an inner staple from said inner row, an intermediate staple from said intermediate row, and an outer staple from said outer row, and wherein said tri-staple driver is positioned proximally with respect to said distal cluster of staple drivers. a tri-staple driver configured to eject three proximal staples from said cartridge body consisting of an inner staple from said inner row, an intermediate staple from said intermediate row, and an outer staple from said outer row, and wherein said tri-staple driver is positioned proximally with respect to said distal cluster of staple drivers.