Chemical reactor engineering, as a discipline, has a central role to play in helping with the development of adequate strategies and technologies that can deal effectively with the concerns of today's society, which are increasingly becoming attuned to the environment. The current challenge is how to adapt present processes and products to meet more rigorous environmental standards. This work addresses these issues in three parts. Attention is also paid, throughout the text, to the fundamental technological aspects of reactor engineering and to possible strategies for bridging knowledge gaps.