Welcome The International Workshop on High Dimensional Data Approximation will be held on November 16-17, 2013 in Sun Yat-sen University, Guangzhou, China. The topics of the workshop include high dimensional data approximation, sparse grid approximation, data mining and adaptive approximation methods in high dimensional spaces. The main objective of this workshop is to bring mathematicians in these related areas to present their recent research results, to exchange new ideas, and to foster research collaboration. On behalf of the organizing committee, it is my pleasure to invite interested researchers and professional experts to participate the workshop. We look forward to welcoming you in Guangzhou. Sincerely yours, Yuesheng Xu On behalf of the Organizing Committee: Ying Jiang, Jie Shen and Yuesheng Xu (Chair)