"Petri Net Algebra" is a specialized book that focuses on the analysis and description of parallel systems in computer science. In an increasingly technology-driven society, computer-based systems are ubiquitous and fundamentally change how businesses operate. The book addresses the complexity of systems composed of many simultaneously active components and provides a comprehensive overview of two of the most commonly used formal models: Petri nets and process algebras. While process algebras utilize algebraic operators to specify and analyze complex systems, Petri nets offer a graphical representation of these systems and enable efficient verification of their correctness. The authors, Maciej Koutny, Eike Best, and Raymond Devillers, combine theoretical foundations with practical applications to convey a deep understanding of the challenges and solutions in the field of parallel systems.