Prof. Zhiwen Yin was Academician of the Chinese Academy of Sciences, former Deputy Director of the Shanghai Institute of Ceramics, Director of the Academic Committee, and a former member of the Ferroelectrics Committee, IEEE-UFFC. Prof. Zhiwen Yin passed away on July 18, 2006 at Shanghai Huadong Hospital, China, at the age of 88. Prof. Yin graduated from the Department of Mining and Metallurgy, Yunnan University in 1942 and received M.S. degrees from the Department of Metallurgy, University of Missouri, Rolla and the Department of Ceramic Engineering, University of Illinois, U.S.A. in 1948 and 1950 respectively. He was elected to be a member of the Chinese Academy of Sciences in 1993. As a materials scientist and Professor of Shanghai Institute of Ceramics, Chinese Academy of Sciences, Prof. Yin devoted his lifetime to the research on functional ceramics, ferroelectrics, and scintillation crystals. He was one of the pioneers in the research and development of the lead zirconium titanate (PZT) piezoelectric ceramics in China and made important contributions to the research and applications of China’s functional ceramic materials. He conducted research work on the phase transition and microstructure changes in relaxor ferroelectrics, PLZT transparent ceramics, and the observation of the nanometer size polar micro-regions in PLZT. He was engaged in the scintillation crystals research since the early 1980’s. After recognizing the radiation damage in the bismuth germanate (BGO) crystal was the result of radiation-induced color centers due to oxygen vacancies in the crystal, he successfully developed a new type of Eu-doped BGO scintillation crystal with high radiation hardness. The scintillation crystal research group led by him provided more than 10,000 pieces of large size BGO crystals for the construction of the electromagnetic calorimeter in the European Nuclear Research Center (CERN). His work on the halide scintillation crystals such as BaF2, CaF2, PbF2, Csl(TI), etc., was also of seminal significance and well recognized worldwide. Prof. Yin was known for his cheerfulness and his contagious laughter. He is missed by the international ferroelectrics community.