This page alphabetically displays the site categories and topic tags with descriptions of the type of material they include. Categories are large buckets containing material largely relevant to the category subject matter. For example, the History category contains books that describe how square dancing evolved, recordings of interviews with prominent figures in the activity, and pointers to websites with historical information. Tags are labels affixed to articles to show that the subject matter indicated by the label is dealt with in some significant way. For example, the History category contains the Sets In Order Archive, which contains digitized copies of the entire SIO publication. Material in that archive deals with Choreography, Recruiting, Equipment, Music, and many other topics. Therefore the article describing the SIO archive, which appears in the History category, is also affixed with those sorts of tags.