Dead Letters: Testy Ideological Letters to No One is a correspondence archive by Jack Feist, dated 7 May 2014 — a composite deposit of 14 blog posts, roughly 50,000 words, published at posthumousoffice.blogspot.com between March and May 2015.
The series is framed as posthumous transcription: letters written to no one, recovered after the writer. That conceit puts it at the origin of the archive's Afterlife genre, which reaches its fullest form in the data-breach corpus (#1279–#1286) a decade later — documents presented as recovered from a vanished source, with the recovery announced rather than concealed.
The deposit is a complete recovered documentary surface, which is the archive's term for a capture that takes a whole publishing channel rather than selected items. Preserving all fourteen posts as one record keeps the series' shape intact.