Astrometry is the oldest of the astronomical endeavors. Indeed, we still have the observing journals of Galileo, the journals of Flamsteed, and those of most of the other old transit-circle astronomers. We have most of the early photographic plates taken for the astrographic catalog project, and almost all the parallax plates. However, as technology progressed, we have become somewhat less precise in recording what we did. It is for this reason that this joint meeting was called: to impress on the modern astronomer that, in general, he only extracts a fraction of the information from his observations, and that these observational data may, in the future, provide an invaluable source needed for the progress of the science.