This book focuses on network structures in biological systems and in human society. The term "network structure" is used in literature with at least two different meanings. The broader meaning (denoted by this author as a network sensu lato) refers to any system composed of nodes (vertices) connected by links (edges). In terms of this interpretation, the analytical tools that deal with centrality measures, clustering, and community structure-related criteria, small-world behaviour, and other network characteristics have provided important insights into the organisation and functioning of various objects, including biological systems and human society. However, there is a narrower interpretation of the term "network" that is predominantly used in the social sciences: a network structure is a decentralised, non-hierarchical system that is regulated by co-operative interactions among its nodes (a network sensu stricto. In this work, the term "networks" is interpreted in the latter sense. The characteristics of a network's organisational situation are considered in this work in comparison to other types of structures that are denoted as (1) hierarchical (vertical, pyramidal) structures characterised by a single dominant activity centre (central leader, pacemaker); and (2) (quasi-)market structures dominated by competitive, rather than co-operative, interactions among the actors involved. This is an interdisciplinary work because the three organisational structures are considered with respect to biological systems and to human society, including its political system.

In the 21st century, the life sciences exert a considerable influence on the humanities and social sciences. People around the world pin their hopes on biology (which can help overcome the ecological crisis and produce new kinds of cheap food) and are concerned about possible risks associated with its developments (such as the possible creation of genetic mutants and cloned humans). Biological knowledge is being increasingly applied to issues related to ethics, linguistics, aesthetics, history, and politics. Biology is currently making a significant contribution to the development of new guidelines concerning the economic and cultural progress of humankind. This book concentrates on an important aspect of the biological mission in the present-day world--on its social and political implications. Taken together, they are referred to as biopolitics in this book.

An overwhelming majority of known species of microorganisms form biofilms (ie: spatially and metabolically structured communities embedded in the extracellular biopolymer matrix). Biofilm development is a complex multi-stage process involving reversible and, at a later stage, irreversible attachment of microbial cells to the substrate surface. Development also involves matrix formation, three-dimensional structuring of the whole community including the formation of mushroom- or pillar-shaped structures and, finally, the degradation of the biofilm and the dispersion of the cells involved. This book examines these processes in the example of microorganisms that interact with the animal or human organisms, playing the roles of symbionts or pathogens.