This and next issues are to celebrate the 70th birthday of our friend, teacher, and mentor, Raghu Varadhan. We would like to thank Raghu for giving us his blessing for this. The Institute of Mathematics is happy to have this honor, as Raghu is the Chair of both its Advisory Committee and Review Committee. Also, this is one way to express our deep appreciation of the worldwide influence of Raghu's scientific works.

Chii-Ruey Hwang, Institute of Mathematics, Academia Sinica, Taiwan.

Tai-Ping Liu, Institute of Mathematics, Academia Sinica, Taiwan, and Department of Mathematics, Stanford University, U.S.A..

Fraydoun Rezakhanlou, Department of Mathematics, University of California Berkeley, U.S.A..

Jeremy Quastel, Department of Mathematics, University of Toronto, Canada.