This paper is a large-scale review of memristive materials, devices and systems. As such it looks into emerging and published work in this field, and reviews the current state of the art. Some of the issues discussed include materials as well as the energy requirements of devices, in addition to their functionality, particularly in computing systems. However, the key issues related to sustainability are not the focus of this work, and thus, any future work aiming to look specifically into the sustainability aspects of this area will need a greater depth of research and understanding.