Different approaches to the problem of training pilots to cope with spatial disorientation are analyzed, with emphasis on those approaches using hardware (antivertigo trainers) specifically designed for such training. Antivertigo trainers are categorized according to function; i.e., as (1) demonstrators of vestibular and visual illusions, (2) demonstrators of spatial disorientation, or (3) trainers to eliminate, through practice, erroneous responses to disorienting stimuli. Simple control-system diagrams of various antivertigo trainers illustrate the critical concepts of identification of the controlled parameter, degree of motion-control-loop closure, cross-sensory-modality coupling, and relevance of vestibular stimulation to the control problem. Opinions regarding probabilities of transfer of the various types of ground-based training to inflight situations are discussed.