The key condition for radical progress in technology in the 21th century is the availability of a technique for the controlled production in a solid of 3D patterns incorporating regions of desired physical and chemical properties, with the possibility of downsizing pattern elements to the nanometer scale being a crucial requirement. In this paper, a method for changing the electrical, magnetic, optical and other key physical properties in a direct and deliberate manner by radically modifying the solid’s atomic composition is proposed for the first time. The physical foundation of the new nonlithography technology is the observation — thoroughly investigated and well verified in our numerous experiments — that accelerated particle beams can be used to selectively remove atoms from thin films of di- or polyatomic compounds. It is shown, in particular, that by selectively removing atoms of a given sort, dielectrics can be transformed into metals or semiconductors, nonmagnetic materials into magnetic ones, and the optical and other properties of materials can be changed radically. The selective removal of atoms of a specified sort from a material is of great interest for future technologies, especially for those relevant to nanoelectronics and, more broadly, to the numerous ’nanoproblems’ ahead in the third millennium.