Articulators are mechanical instruments that represent the maxilla, mandible and TMJs. Very little is known about the origins of dental articulators. Early articulators were based on individual theories of occlusion. The first instrument designs were attempts to duplicate anatomic relationships or reproduce functional movements of the anatomy. More sophisticated articulating instruments evolved as more was learned about anatomy, mandibular movements, and mechanical principles. Regardless of how simple or complex the articulator may be, its effectiveness depends on how well the operator understands its features, the accuracy of registering and transferring jaw relations and how the operator uses it. The large number and great range in complexity of modern articulators can mislead the dentist into thinking that the choice of a suitable instrument is a potentially difficult one. However, the choice is greatly simplified if one considers what records can be obtained accurately, what the instrument will be required to do, and the fact that articulator technology is not a substitute for a biological understanding of the masticatory system.