A linear surgical stapling device comprising: a non-pivotable anvil having a staple forming surface; and a staple cartridge facing the anvil, wherein the staple cartridge comprises: a plurality of staples facing the staple forming surface of the anvil, wherein the staple forming surface of the anvil defines a plurality of staple forming pockets, each pocket aligned with an end of one of the plurality of staples; and a plurality of staple drivers (1012; 1014), wherein each staple driver (1012; 1014) supports one of the plurality of staples and is configured such that, when the staple drivers (1012; 1014) are actuated, each staple driver (1012; 1014) drives the staple into the staple forming surface of the anvil; wherein a first quantity of the plurality of staples have a first pre-formation prong length and a second quantity of the plurality of staples have a second pre-formation prong length, wherein the first pre-formation prong length is less than the second pre-formation prong length characterised in that a first quantity of the plurality of staple drivers (1012; 1014) has a first height and a second quantity of the plurality of staple drivers (1012; 1014) has a second height, wherein the first height is less than the second height; and wherein some of the staple forming pockets are formed in a compliant material portion of the anvil and some of the staple forming pockets are formed in a less-compliant material portion of the anvil. a non-pivotable anvil having a staple forming surface; and a staple cartridge facing the anvil, wherein the staple cartridge comprises: a plurality of staples facing the staple forming surface of the anvil, wherein the staple forming surface of the anvil defines a plurality of staple forming pockets, each pocket aligned with an end of one of the plurality of staples; and a plurality of staple drivers (1012; 1014), wherein each staple driver (1012; 1014) supports one of the plurality of staples and is configured such that, when the staple drivers (1012; 1014) are actuated, each staple driver (1012; 1014) drives the staple into the staple forming surface of the anvil; wherein a first quantity of the plurality of staples have a first pre-formation prong length and a second quantity of the plurality of staples have a second pre-formation prong length, wherein the first pre-formation prong length is less than the second pre-formation prong length characterised in that a first quantity of the plurality of staple drivers (1012; 1014) has a first height and a second quantity of the plurality of staple drivers (1012; 1014) has a second height, wherein the first height is less than the second height; and wherein some of the staple forming pockets are formed in a compliant material portion of the anvil and some of the staple forming pockets are formed in a less-compliant material portion of the anvil. a plurality of staples facing the staple forming surface of the anvil, wherein the staple forming surface of the anvil defines a plurality of staple forming pockets, each pocket aligned with an end of one of the plurality of staples; and a plurality of staple drivers (1012; 1014), wherein each staple driver (1012; 1014) supports one of the plurality of staples and is configured such that, when the staple drivers (1012; 1014) are actuated, each staple driver (1012; 1014) drives the staple into the staple forming surface of the anvil; wherein a first quantity of the plurality of staples have a first pre-formation prong length and a second quantity of the plurality of staples have a second pre-formation prong length, wherein the first pre-formation prong length is less than the second pre-formation prong length characterised in that a first quantity of the plurality of staple drivers (1012; 1014) has a first height and a second quantity of the plurality of staple drivers (1012; 1014) has a second height, wherein the first height is less than the second height; and wherein some of the staple forming pockets are formed in a compliant material portion of the anvil and some of the staple forming pockets are formed in a less-compliant material portion of the anvil.