This second review volume is a follow-up to the book “Engineering of Chemical Complexity” that appeared in 2013. Co-edited by the Nobel laureate Gerhard Ertl, this book provides a broad perspective over the current research aimed at understanding, the design and control of complex chemical systems of various origins, on the scales ranging from single molecules and nano-phenomena to macroscopic chemical reactors. Self-organization behavior and emergence of coherent collective dynamics in reaction–diffusion systems, in active soft matter and biochemical networks are discussed. Special attention is paid to applications in cell biology, to molecular motors and microfluidics effects. The reviews, prepared by leading international experts from the EU, USA, Russia and Japan, together yield a fascinating picture of a rapidly developing research discipline that brings chemical engineering to new frontiers.