An endoscope with guiding apparatus is provided. The endoscope has an elongate body with a steerable distal portion, an automatically controlled portion, a flexible and passively manipulated proximal portion, and an externally controlled and manipulatable guiding apparatus. The guiding apparatus may be positioned within the endoscope or may be positioned adjacent to the endoscope. An interlocking device is provided to slidably interlock the guiding apparatus and the endoscope. When the guide is in a flexible state, it can conform to a curve or path defined by the steerable distal portion and the automatically controlled portion. The guide can then be selectively rigidized to assume that curve or path. Once rigidized, the endoscope can be advanced along the guide in a monorail or "piggy-back" fashion so that the flexible proximal portion follows the curve held by the guide until the endoscope reaches a next point of curvature within a body lumen.