In an era where digital transformation demands ethical foresight and human-centered design, this first volume of a comprehensive trilogy explores how individuals can navigate complexity through responsible technological engagement. By integrating design science research with fuzzy systems theory, it offers a foundation for embedding ethical behavior and sustainable thinking into personal decision-making. The book presents experimentally grounded insights into the scalability and efficiency of human-centric information systems. Volume I introduces fuzzy sets and systems through the ethical lens of the honorable merchant, a holistic concept from medieval Europe. Focusing on the individual level, it explores how humanistic principles inform leadership and responsibility in business informatics, computer science, and engineering. Topics include approximative measurements, reputation management, knowledge carriers, data warehousing, and phenotropic interactions. A responsible actions framework concludes the volume, offering practical guidance for ethically navigating uncertainty in individual contexts. This textbook trilogy is primarily intended for students of computer science, business information systems, and innovation management who aspire to make a meaningful impact. It will also appeal to managers who value balanced perspectives and data-driven analysis.