Pretty-printing can be described as finding a good-looking solution to typeset data according to a set of formatting conventions. Oppen [6] pioneered the field with an algorithmic solution to pretty-printing, using the notions of boxes and break hints. The Format module is a direct descendant of this work: it is unfortunately often misunderstood or even misused. The first goal of this article is to enhance the available documentation about Format by explaining its basic and advanced features but also its relationship and differences with Oppen's seminal work. The second goal is to investigate the links that Format has with the document-based pretty-printing tradition fostered by the lazy programming community [3, 4, 9, 10].