Under the auspices of the Asian Committee for Future Accelerators (ACFA), the 3^rd Asia Particle Accelerator Conference (APAC2004) was held in Gyeongju, Korea, from March 22 through 26, 2004. It was also the third accelerator related international conference held in Gyeongju, Korea, following Linac2002 and ICALEPCS2003.

The Asian Committee for Future Accelerators (ACFA) was established in 1996, and the first Plenary ACFA meeting was held at Pohang Accelerator Laboratory (PAL) in Pohang, Korea. At the meeting it was decided to regularly hold Asian Particle Accelerator Conference (APAC). And the third conference was organized by Pohang Accelerator Laboratory, Pohang University of Science and Technology (POSTECH), Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI). The conference was also benefited from important sponsors including Korea Accelerator and Plasma Research Association (KAPRA) and Association of Asia Pacific Physical Societies (AAPPS), and the Center for High Energy Physics (CHEP).

The Conference was attended by 286 participants from 63 scientific institutes and companies of all over Asia as well as of countries outside Asia. The conference was opened with the welcoming address by Dr. Bon-jae Koo, Director-General of the Ministry of Science and Technology. There were 43 invited talks, 33 oral and 205 poster presentations on various subjects. Among the sessions, the "Free electron lasers and next generation light sources" session was named as the Dr. Hogil Kim Memorial session to pay tribute to the memory of the late Dr. Hogil Kim who founded POSTECH and PAL together with the founder of POSCO, Mr. Tae-Joon Park. We included another special session which covers the subject of high power proton accelerator.

In the afternoon of Wednesday, March 24, the conference outing took place. There were two courses for the outing participants. One included Seokguram Grotto, Bulguksa Temple, and Gyeongju National Museum. The other course was hiking to Mt. Namsan, which is famous as a sacred place of old Shilla culture. After closing the conference on Friday, March 26, the participants and companions had a facility tour of the Pohang Iron and Steel Company (POSCO) and Pohang Accelerator Laboratory. Bedside these outing and tour for all participants, we ran companion programs everyday. Using the programs, the companions could have tours around folk village, museums, historical sites, downtown, and local markets.

We are pleased to be able to offer a place where scientists and engineers shared their valuable knowledge and experiences in accelerator-based sciences, and they could accelerate their scientific and technical understandings as well as strengthen their friendship. We would like to thank all of the members of the International Organizing Committee, the Program Committee, and the Local Organizing Committee. The success of the conference is to be attributed to their enormous efforts.