This chapter gives a good overview of the factors underlying non-visual navigation and a thorough review of the current technology used to support the endeavor. intentionally not exhaustive, the strength of this chapter is that the review is couched in terms of how theories of blind spatial cognition and interface design influence the different sensor technologies and operating environments. The chapter also provides strengths and weaknesses of the various devices and provides the reader with questions to ask when designing or assessing the usability of future technology.