A letter collection consists of a publication, usually a book, containing a compilation of letters written by a real person. Unlike an epistolary novel, a letter collection belongs to non-fiction literature. As a publication, a letter collection is distinct from an archive, which is a repository of original documents.
Usually, the original letters are written over the course of the lifetime of an important individual, noted either for their social position or their intellectual influence, and consist of messages to specific recipients. They might also be open letters intended for a broad audience. After these letters have served their original purpose, a letter collection gathers them to be republished as a group. Letter collections, as a form of life writing, serve a biographical purpose. They also typically select and organize the letters to serve an aesthetic or didactic aim, as in literary belles-lettres and religious epistles. The editor who chooses, organizes, and sometimes alters the letters plays a major role in the interpretation of the published collection. Letter collections have existed as a form of literature in most times and places where letter-writing played a prominent part of public life. Before the invention of printing, letter collections were recopied and circulated as manuscripts, like all literature.
