The first three of the four contributions that make up this volume cover themes that I find particularly interesting and timely. We begin with an account by Yasuo Cho of a form of microscopy, introduced by the author
and his colleagues, with the aid of which the microscopic distribution of polarization in ferromagnetic materials can be visualized directly. Readers of these Advances will not need to be reminded of the importance of ferroelectric materials in modern electronics applications and this technique for observing the essential characteristics of such materials is hence of the highest interest.