The wheelchair has evolved from furniture to vehicle to something akin to custom-made clothing over the last two centuries. Chair and user are interdependent, and in some circumstances, their identities become indistinguishable; the user becomes “enwheeled.”  Scientific and sociological research, as well as life writing, has supported these ideas; in the thesis that follows, I approach the material as a design historian. Using still photographs, trade catalogs, patent filings, records of trade fairs, advertising, and newspaper and magazine articles, I document and examine the wheelchair-user interface in nineteenth-century America. Movies, which began to appear in the 1890s, provide unique opportunities to see the wheelchair and user in motion.  Using several films from 1914 to 2014, the later chapters look at both the evolution of the wheelchair during a time that saw leaps in materials, technology, and disability politics, and the subtleties of human interaction with the group of disparate machines grouped under the heading “wheelchair.”