This book is intended to give an introduction and a comprehensive overview concerning the main areas of surface magnetism with special emphasis on rare earth metals. Investigations in this ?eld require experimental techniques which are sensitive to the topmost layers on the one hand and simultaneously to magnetic properties on the other hand. Using additionally tools with a high lateral resolution the visualization of magnetic domains becomes possible. Theunderstandingofmagneticandelectronicbehaviorrequirestheknowledgeof the structure on a microscopic scale. Due to this important relationship the dep- dence of electronic on structural properties is the ?rst topic. This contains inves- gations not only on rare earth metals but additionally on 3d ferromagnetic systems. It is important to keep in mind that the chemical behavior of a surface det- mines the surface electronic properties. Thus, variations, e.g. due to adsorbate atoms, have a signi?cant in?uence. This aspect will be focused on as the next topic with the description of selected substrate layers which were exposed to different types of gaseous molecules. Investigations on the surface magnetism of itinerant ferromagnetic materials, including the in?uence of adsorbates on surface magnetic properties, and magnets with localized moments is the ?nal and main topic of this volume. It will end with the realization of laterally resolved spin polarized vacuum tunneling which enables to image magnetic domains on the nanometer scale. Acknowledgements This work summarizes my research on the above-mentioned topics performed at the Universities of Bielefeld, Mainz, Hamburg, and Dusseldorf.