A brief introduction will be given on magnetism in nanoscale systems and how size and shape affect magnetic behaviour. The importance of ion beams in the area of nanoscale magnetism will be illustrated with demonstration of dual roles of ion irradiation, namely, transformation of nonmagnetic materials into magnetic materials and vice versa. In the light of the observed phenomena, future developments in the area of nanotechnology, such as ultrahigh density magnetic storage devices, single-electron spin-valve transistors etc. will be discussed. Some nanoscale structures that can be fabricated using ion beams will offer the possibility of exploring new scientific aspects in these structures
