This volume is a collection of selected papers of the Fourth Conference on East Asian and Western Pacific meteorology and climate. It covers remote sensing, atmospheric physics and chemistry, and the impact of aircraft emissions on atmospheric composition, as well as traditional topics like typhoons, rainstorms, monsoons and climate.In July 1989 the first conference in this series took place in Hong Kong. It was run with the innovative bilingual approach, which allowed both Chinese- and English-speaking scientists from various regious of East Asia and across the Pacific to come together, and share and discuss their research. It also proved to be an invaluable networking opportunity leading to a rapid growth of interaction and cooperation among a diverse group of scientists in the decade that followed. The breadth and depth of the presentations at the Fourth Conference was a testimony to the coming of age of this series of conferences, marking the tenth anniversary of an endeavor that had a modest beginning.