Recent advancements of transparent oxide semiconductors (TOS) toward new frontiers of "oxide electronics" are reviewed based on our efforts, categorized as "novel functional materials", "heteroepitaxial growth techniques", and "device fabrications". Topics focused in this paper are: (1) highly conductive ITO thin film with atomically flat surface, (2) p-type TOS material ZnRh2O4, (3) deep-ultraviolet (DUV) transparent conductive oxide beta-Ga2O3 thin film, (4) electrochromic oxyfuolide NbO2F, (5) single-crystalline films of InGaO3(ZnO)(m) grown by reactive solid-phase epitaxy, (6) p-type semiconductor LaCuOS/Se epitaxial films capable of emitting UV- and purple-light, (7) p-n homojunction based on bipolar CuInO2, (8) transparent FET based on single-crystalline InGaO3(ZnO)(5) films, and (9) UV-light emitting diode based on p-n heterojunction. (C) 2003 Elsevier Ltd. All rights reserved.