Abstract: Steerable catheters are achieved using a filament which changes its configuration in response to a changed environmental condition (e.g. temperature) and a controller to change that environmental condition as desired. Alternatively, inflatable members can be used to steer the catheter by deflecting its tip. Catheter propulsion is achieved using an inflatable member which creates a wave-action as it is inflated. Finally, multiple tendons, connected in mirror image positions at the catheter handle and tip, respectively, reflect manipulation of the handle in the tip, to facilitate steering the tip.