These sources examine the evolution and application of systems thinking and operations research, with a primary focus on Peter Checkland’s Soft Systems Methodology (SSM). The texts contrast “hard” systems engineering, which pursues defined goals through mathematical modelling, with “soft” approaches designed to navigate messy, ill-structured human problems. They explore the historical transition from scientific reductionism to holism, arguing that complex social and biological entities possess emergent properties that cannot be understood by merely studying individual parts. Practical applications are discussed across diverse fields, including information systems strategy, healthcare management, and military logistics. By using conceptual models and root definitions, the authors demonstrate how subjective worldviews can be harnessed to facilitate organisational learning and purposeful change. Ultimately, the collection highlights the necessity of viewing information systems as support structures for human activity rather than isolated technical tools.