The book "Network Alignment: From Pairwise To Multiple" offers a comprehensive introduction to the formal elaboration of network alignments. It addresses the combination of genomic sequence information and protein-protein interaction networks (PPI) to identify conserved interaction regions across different species. A central theme is the search for functional homologs in various organisms, which is considered an NP-hard problem. The work presents both the HopMap and Mawish extension algorithms for pairwise alignment, which are characterized by high specificity and sensitivity. For multiple alignment, the HopeMap-M algorithm is introduced, capable of aligning ten networks with tens of thousands of proteins in less than a few minutes. Additionally, the parametric complexity of the Multi-MCS is derived for various parameters and graph classes.