Half title

"The half-title or bastard title is a page carrying nothing but the title of a book," where the title page "also lists subtitle, author, publisher and edition." It is "usually counted as the first page (p. i) in a printed book," may be plain or ornamented, and its original job was protective: "to protect the full title page and its traditional counterpart, the frontispiece" during binding, since it "serves as the outermost layer of paper at the front of the book" while finished blocks await their covers. Older usage split the terms: in de Vinne's distinction the "bastard title...precedes the full title."

For the self-publisher it is the first page of front matter: KDP's canonical order opens with it, unnumbered, and the frontispiece waits opposite the title page. The build order is how to create a print-ready PDF.