This open access book overviews cutting-edge research on thermocapillary convection driven by temperature dependence of surface tension. A notable feature of the book is that it is concerned with a series of experiments performed under microgravity in the Japanese experimental module Kibo aboard the International Space Station (ISS). Also described are related topics such as onboard experimental apparatus, executing procedures, international collaborations, preceding terrestrial studies, and their many outcomes. Further, it presents insights into applications of capillarity to microelectromechanical systems (MEMS), micro-total analysis systems (µTAS), material processing, and future human space exploration, where surface tension must play a major role instead of gravity.Intended as a pedagogical introduction for readers who are not familiar with this subject, the book also skillfully reviews fundamental physics and analysis of thermocapillary convection, describing phenomenology and theory of surface tension, analysis of a transition threshold to unsteady flows, and computational methods for flow and temperature fields. It is thus a valuable resource for graduate students, young researchers, and engineers who are interested in related topics, and enables them to quickly catch up with the latest research from basic to applied to thermofluid dynamics subject matter to microgravity science and technology.