The ability to understand and control the unique properties of interfaces has created an entirely new field of magnetism, with profound impact in technology and serving as the basis for a revolution in electronics. Our understanding of the physics of magnetic nanostructures has also advanced significantly. This rapid development has generated a need for a comprehensive treatment that can serve as an introduction to the field for those entering it from diverse fields, but which will also serve as a timely overview for those already working in this area. The four-volume work Ultra-Thin Magnetic Structures aims to fulfill this dual need. The original two volumes - now available once more - are "e;An Introduction to the Electronic, Magnetic and Structural Properties"e; (Vol. I) and Measurement Techniques and Novel Magnetic Properties (this volume). Two new volumes, "e;Fundamentals of Nanomagnetism"e; and "e;Applications of Nanomagnetism,"e; extend and complete this comprehensive work by presenting the foundations of spintronics.