Abstract: Recent paleontological and neontological studies on feathers and feather-like integumentary structures have improved greatly our understanding of the origin and early evolution of feathers. New observations on some non-avian dinosaur specimens preserving integumentary structures, in combination with recent paleontological and neontological data, provide additional insights into this important evolutionary issue. Five major morphogenesis events are inferred to have occurred sequentially early in feather evolution before the origin of the Aves, and they are: 1) appearance of filamentous and tubular morphology, 2) formation of follicle and barb ridges, 3) appearance of rachis, 4) appearance of planar form, and 5) formation of pennaceous barbules. These events produce several morphotypes of feathers that are common among non-avian archosaurs but are probably lost later in avian evolution, and they also produced several morphotypes of feathers that are nearly identical or identical to those of modern birds. While feathers of non-avian dinosaurs exhibit many unique features of modern feathers, some of them also possess striking features unknown in modern feathers. Several models of evolutionary origin of feathers based on developmental data suggest that the origin of feathers is a completely innovative event and the first feathers have nothing to do with reptilian scales. We believe, however, that the defining features of modern feathers might have evolved in an incremental manner rather than in a sudden way. Consequently, an evolutionary model characteristic of both transformation and innovation is more acceptable for feather evolution. The function of the first feather is inferred to be neither related to flight nor to insulation. Display or heat dissipation, among others, remains viable hypotheses for initial function of feathers. An integrative study is promising to provide much new insights into the origin of feathers.