The WWP encodes short prose works identified by the text as “essays” using <div type="essay">. However, short prose pieces appearing in the front matter are encoded with <div type="prefatory">; this value overrides the value “essay” in the same way it overrides the value “letter”.
Works of poetry which are called “essays” are tagged as <div type="poem">.
In most cases, when prose essays are printed as a collection, they function as part of the collection and are treated as subdivisions (and hence are encoded with <div>). However, in rare cases where each essay is presented with its own front and back matter, we treat the collection as a <group> and each essay as a <text>, with its own <front>, <body>, and <back>.