The Proceedings in this volume are a refereed selection of presentations from The Third Asia-Pacific EPR/ESR Symposium (APES'01), held in Kobe, Japan from October 29 to November 1, 2001. Participants from 20 countries from Asia, Australia, Europe, North and South America presented 210 papers, of which 132 are included here.These Proceedings are also a blueprint for development of electron paramagnetic resonance (EPR) / electron spin resonance (ESR) in the Asia-Pacific region in the 21st century. The Symposium reflected a variety of research fields developed over half a century and focuses especially on the most recent developments, such as high-field and high-frequency EPR, which are envisaged to be further developed and applied to various fields in the 21st century.All sessions consisted of Plenary, Invited and Contributed presentations. The Plenary presentations aimed at summarizing the overall developments. Invited presentations, reviewing the most recent developments, and Contributed ones, dealing with original research recently carried out in the EPR/ESR area, were given in one of three parallel sessions. The unique research works presented cover various fields and reflect the existing diversity of applications of the EPR/ESR techniques.