The physiologic three-dimensional movements of the mandible are best described in terms of the physiologic axes of rotation and their associated planes of motion. The various types of working condyle motions (mainly rotation, rotation with lateral movement, and rotation with inclined lateral movement) have a profound effect on the three-dimensional path of the balancing condyle and the resulting cuspal anatomic condition. During laboratory construction, the individual condylar paths and the incisal guidance determine the orientation of the occlusal plane and the cusp inclines. Only the Gnathologic type of instrument accurately imitates the individual spacial condylar relationships. From a practical standpoint, however, the Hanau type of adjustable articulator affords most dentists an excellent instrument for the construction of harmonious restorations if its limitations are understood. Some intraoral occlusal equilibration is necessary with either instrument.