The "Name Authority Heading" or the "Uniform Name Title" are designations for a particular variant of the composer's name that is standardized for the entire national library system. That is to say, the Name Authority it is the official name by which all records in all national libraries will classify certain person. Thus it should not matter what actual name variant may appear on some manuscript, a score, a book or an article, as the author's name will always appear in catalogs the same way, and can likewise be searched (and found) as such efficiently.
It is important to note that the Name Authority can actually be changed over a period of time, pending the user preferences, commonality in publications and the other factors. Furthermore, the Name Authority can differ from country to country as well. In the case of Johann Matthias Sperger for example, the current Name Authority (as determined by the Library of Congress) and the German Name Authority (as determined by the Deutsche National Bibliothek) - actually differ. The German one goes by the baptismal "Johannes" and the American goes by the common"Johann". In most cases however the Name Authorities will be the same within western countries.
If interested to find out more on this subject you are welcome to visit the Library of Congress Authorities site, which explains this system in greater detail.
Aside form the Name Authorities, there are also the "Title", the "Name/Title" and the "Subject Heading" authorities. At this stage, you will find on this site only the Name Authorities applied. However in the future, when the individual composition pages start to appear, the Title and Name/Title authorities will be introduced too, since this is the best way to prevent confusion or misattribution between the authors and their works.
More on the actual reasons that have prompted the creation national Name Authorities systems, you can also follow in the Name Variants section.
Posted: September 30, 2010.