This book follows on from Volume 83 in the SCBI series (“Macromolecular Protein Complexes”), and addresses several important topics (such as the Proteasome, Anaphase Promoting Complex, Ribosome and Apoptosome) that were not previously included, together with a number of additional exciting topics in this rapidly expanding field of study. Although the first SCBI Protein Complex book focused on soluble protein complexes, the second (Vol. 87)addressed Membrane Complexes, and the third (Vol. 88) put the spotlight on Viral Protein and Nucleoprotein Complexes, a number of membrane, virus and even fibrillar protein complexes have been be considered for inclusion in the present book. A further book is also under preparation that follows the same pattern, in an attempt to provide a thorough coverage of the subject.Chapter 9 is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.