This fourth spillover conference in Dalian exhibits advances and new results in spillover studies since 1993. In the proceedings, 5 invited lectures, 23 oral and 28 poster presentations are collected. In the 5 invited lectures, the active research areas are reviewed by well recognized scientists in the relevant fields. The first lecture highlights the fact that spillover plays a significant role in controlling the dynamic state of catalysts when it occurs in the catalytic process. The second lecture studies the surface mobility of oxygen and hydrogen using isotopic exchange method, and the impact of surface mobility on many catalytic processes is discussed. In the third paper the acidic functions of spilt-over hydrogen in a number of acid catalyzed reactions are well clarified. Subsequently, the fourth lecture explores electrochemically controlled spillover phenomenon over mm distances directly observed on metal catalysts. Finally, the last lecture reports the spontaneous dispersion of compounds onto supports and its importance in catalysis, and concludes that surface migration is a quite common process. The conference papers present a number of aspects of spillover studies, such as new spillover phenomena, new methods for spillover characterization, spillover effects in catalysis, etc. Studies on migration and mobility of surface species are also included in the conference topics, as it is believed that the migration of species is a more general phenomenon, and spillover can be considered as a special case of migration. The spillover of hydrogen and oxygen is the major issue at the conference, while the spillover of larger molecules are reported as well in some papers. Simulation and modeling of spillover and surface mobility are also a very interesting subject in the meeting.