Materials Science & Engineering R: Reports publishes invited review papers covering the full spectrum of materials science and engineering. The reviews, both experimental and theoretical, provide general background information as well as a critical assessment on topics in a state of flux. The editorial policy of Materials Science & Engineering R: Reports is to serve its readership in two ways. Firstly, it provides a critical overview of the current issues in a well-defined area of immediate interest to materials scientists. Secondly, each review contains an extensive list of references thus providing an invaluable pointer to the primary research literature available on the topic. This policy is implemented by the Editorial Board which consists of outstanding scientists in their respective disciplines. The Board identifies the topics of interest and subsequently invites qualified authors. In order to ensure speedy publication, each review is published separately.