1. A method to enable a user-object to communicate using gestures made in (x,y,z) space with an electronic device coupleable to a display screen whereon imagery is displayable, the method including the following steps: (a) providing said electronic device with an optical acquisition system operable to capture image data of said user-object within a three-dimensional hover zone; (b) defining within said three-dimensional hover zone an interaction subzone including at least one z 0 plane disposed intermediate a plane of said display screen and a plane at a maximum z-distance beyond which user-object gestures need not be recognized by said electronic device; (c) processing image data captured at step (a) representing an interaction of said user-object with at least a portion of said z 0 plane, defined in step (b), to detect and to produce three-dimensional positional information of said interaction; (d) using said three-dimensional positional information produced at step (c) to determine at least one of (i) when in time, and (ii) where in (x,y,z) space said user-object interacted with said z 0 plane; (e) following determination at step (d), identifying a gesture being made by said user-object; and (f) in response to identification of a gesture at step (e), altering at least one operating characteristic of said electronic device.