20th century dancing is now being studied using the same methods that have been applied to earlier periods. The written sources are, in principle, far more abundant and detailed (not only instruction manuals, but newspapers, magazines, posters, and programmes), but, in practice, they are still frustratingly difficult to locate. We have recorded music (on wax, shellac, vinyl, magnetic tape, CD, and digital media), but it is the invention of moving pictures, captured on photographic film or video, that has revolutionised our ability to study the actual movements of dancers in the 20th century. Nevertheless, even these are not universally available and do not always give the complete picture, so established methods of historical research are still required.
