Professor Yoshio Sone of Kyoto University turned seventy in 2006. As the world leader in molecular gas dynamics, the research of Professor Sone is also deeply mathematical. For this reason, his many mathematical friends around the world would like to celebrate this occasion by dedicating issues in a mathematical journal in his honor. This and the previous issue of the Bulletin of the Institute of Mathematics, Academia Sinica represent the fruition of this idea. We are very pleased with this publication and deeply thank all of the authors for their contributions.

The choice to publish in the Bulletin signals the growing influence of Professor Sone’s research to the mathematical community throughout the world. Both issues reflect the impact of Professor Sone's work. Introduction to the previous issue that briefly summarizes the research of Professor Sone may help the reader better understand his deep and broad contributions. The mathematical community will continue to enjoy the intellectual exchanges with Professor Sone in the years to come.

Kazuo Aoki, Department of Mechanical Engineering and Science, Kyoto University, Japan.

François Golse, Centre de Math&eacut;matiques Laurent Schwartz, Ecole Polytechnique, France.

Tai-Ping Liu, Institute of Mathematics, Academia Sinica, ROC, and Department of Mathematics, Stanford University.

Shih-Hsien Yu, Department of Mathematics, National University of Singapore, Singapore.