In the 15th and 16th century (though it still occurs, but rarely) all books were handset with lead type. One can understand that a printer, who undertook the massive task of setting every single page of a book, by hand, could use a shout-out somewhere. And so a colophon page served this purpose.
The colophon (example at left) is a portion of books which is rarely included these days. One could view it as a prose version of a copyright page. The most comprehensive colophon outlines the typeface, paper and manner of printing used, and the printer or printing house, and publishing house responsible for the book's existence.
I have set type by hand. In fact, I do so with some regularity and I really enjoy it. But having dealt with business cards, greeting cards and various pieces of correspondence, I have only a vague idea of what it would be like to set an entire book.
It takes a special passion. Setting type is a very mechanical undertaking with a final product that is a piece of art. So the process of production requires a person with not only the patience and diligence to get through it, but someone who can evaluate a typographic layout, and adjust it according to an artful eye.
This scan was sent in by Peter Ahlberg, a great designer who I have known for many years. He thought that the last line was really important.