A device for one-handed insertion of a guidewire, comprising: a syringe having: a plunger, a plunger flange and a guidewire passage through said plunger and a hollow needle co-linear with said guidewire passage through said plunger; said device being characterized by a body having: a handle formed in said body, a guideway defined by said body, a mount adapted to receive and retain a barrel of the syringe, the mount having a trap mounted on said body; and an actuator carriage slidable along said guideway of said body, having attached thereto: a trigger, a flange trap adapted to grasp the plunger flange of the syringe, a wire guide feed mount adapted to support a generally annular cassette mounted on said actuator carriage and having mounted thereupon: a guide fitting adapted to couple with said plunger flange and direct said guidewire into said guidewire passage through the plunger of said syringe; and a wire feed surface between said generally annular cassette and said guide fitting, and a receiver adapted to couple with said generally annular cassette, wherein said handle, said trigger and said wire feed surface are disposed such that when the handle is engaged by the digits of one hand, a digit of said one hand is able to advance the wire through said syringe by engaging the guidewire between the digit of said one hand and the wire feed surface, sensing the degree of resistance encountered by the tip of said guidewire, with a digit of said one hand being able to urge the trigger rearwardly and/or forwardly, drawing said plunger rearwardly and/or forwardly while digits of said one hand continue to engage said handle. a plunger, a plunger flange and a guidewire passage through said plunger and a hollow needle co-linear with said guidewire passage through said plunger; said device being characterized by a body having: a handle formed in said body, a guideway defined by said body, a mount adapted to receive and retain a barrel of the syringe, the mount having a trap mounted on said body; and a handle formed in said body, a guideway defined by said body, a mount adapted to receive and retain a barrel of the syringe, the mount having a trap mounted on said body; and an actuator carriage slidable along said guideway of said body, having attached thereto: a trigger, a flange trap adapted to grasp the plunger flange of the syringe, a wire guide feed mount adapted to support a generally annular cassette mounted on said actuator carriage and having mounted thereupon: a guide fitting adapted to couple with said plunger flange and direct said guidewire into said guidewire passage through the plunger of said syringe; and a wire feed surface between said generally annular cassette and said guide fitting, and a receiver adapted to couple with said generally annular cassette, wherein said handle, said trigger and said wire feed surface are disposed such that when the handle is engaged by the digits of one hand, a digit of said one hand is able to advance the wire through said syringe by engaging the guidewire between the digit of said one hand and the wire feed surface, sensing the degree of resistance encountered by the tip of said guidewire, with a digit of said one hand being able to urge the trigger rearwardly and/or forwardly, drawing said plunger rearwardly and/or forwardly while digits of said one hand continue to engage said handle. a trigger, a flange trap adapted to grasp the plunger flange of the syringe, a wire guide feed mount adapted to support a generally annular cassette mounted on said actuator carriage and having mounted thereupon: a guide fitting adapted to couple with said plunger flange and direct said guidewire into said guidewire passage through the plunger of said syringe; and a wire feed surface between said generally annular cassette and said guide fitting, and a guide fitting adapted to couple with said plunger flange and direct said guidewire into said guidewire passage through the plunger of said syringe; and a wire feed surface between said generally annular cassette and said guide fitting, and a receiver adapted to couple with said generally annular cassette, wherein said handle, said trigger and said wire feed surface are disposed such that when the handle is engaged by the digits of one hand, a digit of said one hand is able to advance the wire through said syringe by engaging the guidewire between the digit of said one hand and the wire feed surface, sensing the degree of resistance encountered by the tip of said guidewire, with a digit of said one hand being able to urge the trigger rearwardly and/or forwardly, drawing said plunger rearwardly and/or forwardly while digits of said one hand continue to engage said handle.