Special Issue on Progress of Vacuum and Surface Science and Technology in the Early 21st Century --the 20th Anniversary of e-JSSNT--.

E-Journal of Surface Science and Nanotechnology (e-JSSNT) is an electric journal published by the Japan Society of Vacuum and Surface Science since 2003, and this year marks its 20th anniversary. To commemorate this event, a special issue "Progress of Vacuum and Surface Science and Technology in the Early 21st Century" is published with six papers from different research fields reviewing research progress over the past 20 years (or since the beginning of the 21st century). We hope that this issue will give each researcher a hint for future research development by looking back the paths we have taken. The preface and the review papers are also published in English in e-JSSNT, Vol. 21, Issue 2. [ABSTRACT FROM AUTHOR]