The Journal of Mineralogical and Petrological Sciences (JMPS) publishes original articles, reviews and letters in the fields of mineralogy, petrology, economic geology, geochemistry, planetary materials science, and related scientific fields. As an international journal, we aim to provide worldwide diffusion for the results of research in Japan, as well as to serve as a medium with high impact factor for the global scientific communication Given the remarkable rate at which publications have been expanding to include several fields, including planetary and earth sciences, materials science, and instrumental analysis technology, the journal aims to encourage and develop a variety of such new interdisciplinary scientific fields, to encourage the wide scope of such new fields to bloom in the future, and to contribute to the rapidly growing international scientific community. To cope with this emerging scientific environment, in April 2000 the journal's two parent societies, MSJ* (The Mineralogical Society of Japan) and JAMPEG* (The Japanese Association of Mineralogists, Petrologists and Economic Geologists), combined their respective journals (the Mineralogical Journal and the Journal of Mineralogy, Petrology and Economic Geology). The result of this merger was the Journal of Mineralogical and Petrological Sciences, which has a greatly expanded and enriched scope compared to its predecessors.