This is a bilingual edition of Ernst Mach's classic 1875 text on the vestibular system. Mach was an eminent physicist who worked on the speed of sound (Mach as the unit of sound speed), on visual perception (Mach bands which describe contrast phenomena), mechanics (Einstein specifically refers to him as a decisive influence), and created the philosophical foundation of positivism. Mach's work is central to the consideration of processing and human movement perception - a topic of considerable current interest. The early insights and examples Mach provides are instructive, and largely unknown nowadays. Bound along with the text is a CD-ROM, which includes, among other things, the English version of the text, extensive biographies, references, articles, and links to the footnotes.