Galactic Astronomy is, and for some time to come will certainly remain, one of the more important items in the astronomy curricula. There are at present a number of excellent text-books and monographs covering the whole subject or certain of its aspects. It seems however that there is not a single book where at least some of the more important problems dealt with in text-books and university courses would be presented in the form of laboratory exercises. This short series of exercises represents an attempt to fill this gap. What is, in general, the aim of such exercises? As to this point, the...