In this volume of ASPA, devoted to developmental biology research, 9 authors from different fields of developmental biology present their investigations on various developing plant and animal models. An a priori concern in mind that weightlessness might have negative effects on developmental processes, it is encouraging to know that the overall development of various organisms tested so far is essentially correct under spaceflight conditions, leading to viable individuals with viable offspring. On the other hand, particular studies on specifically neurophysiological aspects in developing organisms reveal important flight or postflight disturbances; however it is encouraging to know that they appear to be transient only.The book contains ten chapters, giving details on how, in technical terms, experiments for spaceflights are prepared, performed and analysed and on how, in scientific terms, the available results have to be interpreted. One contribution is devoted to plant systems, five consider the overall aspects of embryonic development in invertebrates and vertebrates, two focus on neurophysiological aspects and one reports on the "mother-offspring system" in weightlessness in a mammalian model, the last chapter presents new ESA facilities and instruments to be integrated into the European research Laboratory "Columbus" of the ISS.