A materials handling vehicle comprising: a vehicle body, a plurality of wheels supporting the vehicle body, a traction control unit braking system, and a steering; assembly, each operatively coupled to one or more of the vehicle wheels, a mast assembly; and a mast assembly control unit, and a fork carriage assembly, wherein the mast assembly and the mast assembly control unit are configured to move the fork carriage assembly along a vertical axis Z', and characterized in that the materials handling vehicle further comprises: a picking attachment secured to the fork carriage assembly and comprising an X-Y-Z-Ψ positioner, and one or more vehicular controllers in communication with the traction control unit, the braking system, the steering assembly, the mast assembly control unit, and the picking attachment, wherein the one or more vehicular controllers of the materials handling vehicle is configured to execute vehicle functions to use the X-Y-Z-Ψ positioner of the picking attachment to engage and disengage a target tote positioned in a multilevel warehouse racking system with the picking attachment, and the mast assembly, the mast assembly control unit, and the picking attachment are collectively configured such that movement of the picking attachment along a Z axis by the X-Y-Z-Ψ positioner is independent of movement of the fork carriage assembly along the vertical axis Z' by the mast assembly and mast assembly control unit. a vehicle body, a plurality of wheels supporting the vehicle body, a traction control unit braking system, and a steering; assembly, each operatively coupled to one or more of the vehicle wheels, a mast assembly; and a mast assembly control unit, and a fork carriage assembly, wherein the mast assembly and the mast assembly control unit are configured to move the fork carriage assembly along a vertical axis Z', and characterized in that the materials handling vehicle further comprises: a picking attachment secured to the fork carriage assembly and comprising an X-Y-Z-Ψ positioner, and one or more vehicular controllers in communication with the traction control unit, the braking system, the steering assembly, the mast assembly control unit, and the picking attachment, wherein the one or more vehicular controllers of the materials handling vehicle is configured to execute vehicle functions to use the X-Y-Z-Ψ positioner of the picking attachment to engage and disengage a target tote positioned in a multilevel warehouse racking system with the picking attachment, and the mast assembly, the mast assembly control unit, and the picking attachment are collectively configured such that movement of the picking attachment along a Z axis by the X-Y-Z-Ψ positioner is independent of movement of the fork carriage assembly along the vertical axis Z' by the mast assembly and mast assembly control unit. a picking attachment secured to the fork carriage assembly and comprising an X-Y-Z-Ψ positioner, and one or more vehicular controllers in communication with the traction control unit, the braking system, the steering assembly, the mast assembly control unit, and the picking attachment, wherein the one or more vehicular controllers of the materials handling vehicle is configured to execute vehicle functions to use the X-Y-Z-Ψ positioner of the picking attachment to engage and disengage a target tote positioned in a multilevel warehouse racking system with the picking attachment, and the mast assembly, the mast assembly control unit, and the picking attachment are collectively configured such that movement of the picking attachment along a Z axis by the X-Y-Z-Ψ positioner is independent of movement of the fork carriage assembly along the vertical axis Z' by the mast assembly and mast assembly control unit. the one or more vehicular controllers of the materials handling vehicle is configured to execute vehicle functions to use the X-Y-Z-Ψ positioner of the picking attachment to engage and disengage a target tote positioned in a multilevel warehouse racking system with the picking attachment, and the mast assembly, the mast assembly control unit, and the picking attachment are collectively configured such that movement of the picking attachment along a Z axis by the X-Y-Z-Ψ positioner is independent of movement of the fork carriage assembly along the vertical axis Z' by the mast assembly and mast assembly control unit.