Twisted Magnetic Phases* S. D. Bader Materials Science Division Argonne National Laboratory Argonne Magnetism is one of the oldest fields in science but it is also at the forefront of the nanotechnology revolution. This talk draws on historical roots to provide a modern experimental perspective on recent issues and challenges in the field. Highlighted areas include the importance of novel interfacial magnetic coupling phenomena. Examples of how nanotechnology provides new strategies to realize composite magnetic materials with exceptional properties and interesting physics will be presented. A main theme will be the experimental verification of theoretically predicted magnetic phases with non-collinear (twisted) magnetic structures. * Work supported by the US DOE Office of Science, contract #W-31-109-ENG-38.