Despite intensive study and a number of remarkable discoveries in the last two decades of the 20th century, our understanding of the cultural and biological processes that resulted in the emergence of the Upper Paleolithic and the establishment of modern humans in Interpleniglacial Europe remains far from complete. There is active debate concerning the timing and location of the origins of the Aurignacian, the nature of the origins of Initial Upper Paleolithic industries (whether by autochthonous development or through acculturation by Aurignacian peoples), the timing of the appearance of early modern humans and the disappearance of the Neandertals, and the relationship of archeologically defined cultures to these different types of hominids. Frustrating our attempts to address these latter two questions is a general paucity of taxonomically diagnostic human fossil material from early Upper Paleolithic contexts. We undertake here a review of the human fossil record of Interpleniglacial Europe, and its archeological and chronological context, to clarify to the extent possible the nature of the relationship between hominid groups and the earliest Upper Paleolithic artifact industries, particularly the early Aurignacian. Although substantial difficulties involved in interpreting the fossil, archeological, and geochronological records of this time period prohibit making any definitive statements, a number of observations are suggested by the current data: 1) the Middle Paleolithic of Europe appears to have been made exclusively by Neandertals; 2) Initial Upper Paleolithic industries (with the exception of the Bachokirian) appear to have their roots in the late Middle Paleolithic industries of their respective regions; 3) all of the human fossils yet recovered from Initial Upper Paleolithic (except the Bachokirian) contexts for which any diagnostic morphology is present have their greatest morphological affinities with Neandertals and not early modern humans; 4) modern humans were almost certainly established in Europe by ca. 32 ky BP, with a strong possibility that they were there by ca. 36 ky BP. Claims for an appearance before 36 ky BP cannot be substantiated with currently available evidence; 5) the hypothesis that modern humans are uniquely associated with the Aurignacian cannot yet be refuted. Aurignacian-associated human fossils (including those from the Bachokirian) for which any diagnostic morphology is present have their greatest affinities with early modern Europeans and not Neandertals; and 6) Neandertals and modern humans coexisted in Europe for at least 2,000–4,000 years, and perhaps for 8,000–10,000 years or longer. The overall picture is one of an extended period of cultural contact, involving some degree of genetic exchange, between Neandertals and early modern Europeans. Yrbk Phys Anthropol 43:61–115, 2000. © 2000 Wiley-Liss, Inc.