Half-Title Page: In publishing’s early days, books were sold unbound. This custom allowed the purchaser to select their own binding material in a colour of their own choosing when they could afford it. Unfortunately, this also meant that the loose piles of paper were subjected to extra handling, and were at risk of being damaged. In order to protect the manuscript’s, often decorative, Title Page during transport, booksellers topped the pile with a single sheet of paper holding only the title.
Originally called the Bastard-Title Page, this practice has become tradition and, even though we buy our books bound, today, with the title on the cover, the half-title page is still a part of every book.