Abstract: A pen adapted to be flat, when not being used for writing, can be used as a bookmark, when unfolded into such a flat shape. The pen has three flat panels with one of the panels being connected to each of the other panels at opposite longitudinal edges by hinges, so that all three panels lie in the same plane when the pen is unfolded. One of the panels has a hollow reservoir for storing and dispensing ink. A pen tip for dispensing the ink extends into the hollow reservoir.