The CSEAS library has been a most essential foundation on in the promotion of research activities in the ﬁeld of Southeast Asian studies. As the result of ongoing collection development focusing on academic publications on Southeast Asia, the library holds approximately 253,000 items and assures access by both domestic and overseas patrons through its open access policy and reference services. The library has strong emphasis on the publications published in Southeast Asia and especially, for the Thailand and Indonesia, up to date book acquisitions are operated through The CSEAS overseas liaison oﬃces in Bangkok and Jakarta. In addition, the library also collects many archival materials from colonial period in Microﬁlm form.
While the library is devoted to collecting and providing access to historical documents and academic works on Southeast Asia, it is also keen on responding to the changes in Southeast Asia and working together with researchers. For example, the CSEAS co-research program now has a special slot for document based on research and provides suﬃcient funding for acquisition of library materials related to proposed documents based research. This open and collaborative atmosphere of the library is also created by the librarians that the library receives as foreign fellows. Over the past 20 years since 1986, many librarians from Southeast Asia and United States have spent 6 months at the library and not only pursued their academic research interest but also contributed to the development of the library in various ways. We are looking forward to working many others in the near future.