34th International Symposium on Superconductivity (ISS2021)It is our pleasure to report that the Proceedings of the 34th International Symposium on Superconductivity (ISS2021) held on November 30–December 2, 2021, are now published in Journal of Physics: Conference Series (JPCS). ISS2021 was co-organized by the National Institute of Advanced Industrial Science and Technology (AIST) and the Victoria University of Wellington (VUW). At first, ISS2021 was planned to be held on site in Wellington, New Zeeland. However, owing to the continued travel restrictions by COVID-19 pandemic, the symposium was held online with using the “Cisco Webex Meetings” application. Although most of presentations were smoothly made, several presentations were cancelled probably due to limited speed of a communication line, some of which were re-scheduled and presented at later dates.Total of 342 scientists, engineers, students, corporate executives and so on (107 from abroad) made advanced registrations for ISS2021, and fruitful discussions were made to promote superconductor sciences and technologies. Total of 215 papers were presented, which included 5 plenary lectures (45 min), 76 invited talks (25–30 min) and 134 contributed oral presentations (15–20 min). Among the papers presented in ISS2021, 41 manuscripts were submitted for ISS2021 Proceedings, and 39 papers were accepted for publication. The papers published in JPCS were categorized into relevant topics in the following four fields; (a) Physics and Chemistry, (b) Wires and Bulk, (c) Electronic Devices, (d) Large Scale System Applications.To ensure the high publication standard mandated by JPCS, every paper was peer reviewed by a reviewer with expertise before it was accepted for publication. As editors of the Proceedings, we would like to express our sincere appreciation to all the reviewers involved in the evaluation of the papers for their invaluable contribution. The Editors Physics and Chemistry: Atsutaka Maeda (The University of Tokyo), Hiraku Ogino (AIST)Wires and Bulk: Yoshiyuki Yoshida (AIST), Yasuhiro Iijima (Fujikura Ltd.), Yasunori Mawatari (AIST)Electronic Devices: Mutsuo Hidaka (AIST), Tsunehiro Hato (SUSTEC)Large Scale System Applications: Naoyuki Amemiya (Kyoto University), Tsuyoshi Wakuda (Hitachi Ltd.), Hiroshi Miyazaki (Kyushu University)List of Organization of ISS2021, Committees of ISS2021, International Advisory Committee are available in this Pdf.