A surgical stapler comprising: (a) a first elongate member having a distal portion that supports an anvil surface, wherein the anvil surface includes a plurality of staple forming pockets; (b) a second elongate member having a distal portion configured to receive a staple cartridge; (c) a clamp member operable to releasably clamp the first elongate member against the second elongate member; (c) a firing assembly, wherein the firing assembly is translatable from a first longitudinal position to a second longitudinal position to fire the staple cartridge when the first elongate member is clamped against the second elongate member; and (d) a retaining assembly, wherein the retaining assembly comprises: (i) a first retaining member configured to releasably couple a proximal end of the first elongate member with a proximal end of the second elongate member, and (ii) a second retaining member configured to releasably retain the firing assembly in the first longitudinal position, wherein characterized in that: the first retaining member comprises a latch member, wherein the second retaining member comprises a detent member, wherein the clamp member is moveable from an unclamped position to a clamped position to clamp the first elongate member against the second elongate member, wherein the detent member is configured to prevent the clamp member from returning to the unclamped position from the clamped position when the firing assembly is advanced longitudinally away from its first longitudinal position. (a) a first elongate member having a distal portion that supports an anvil surface, wherein the anvil surface includes a plurality of staple forming pockets; (b) a second elongate member having a distal portion configured to receive a staple cartridge; (c) a clamp member operable to releasably clamp the first elongate member against the second elongate member; (c) a firing assembly, wherein the firing assembly is translatable from a first longitudinal position to a second longitudinal position to fire the staple cartridge when the first elongate member is clamped against the second elongate member; and (d) a retaining assembly, wherein the retaining assembly comprises: (i) a first retaining member configured to releasably couple a proximal end of the first elongate member with a proximal end of the second elongate member, and (ii) a second retaining member configured to releasably retain the firing assembly in the first longitudinal position, wherein characterized in that: the first retaining member comprises a latch member, wherein the second retaining member comprises a detent member, wherein the clamp member is moveable from an unclamped position to a clamped position to clamp the first elongate member against the second elongate member, wherein the detent member is configured to prevent the clamp member from returning to the unclamped position from the clamped position when the firing assembly is advanced longitudinally away from its first longitudinal position. (i) a first retaining member configured to releasably couple a proximal end of the first elongate member with a proximal end of the second elongate member, and (ii) a second retaining member configured to releasably retain the firing assembly in the first longitudinal position, wherein