How do people learn to feel safe with others?  How do early relationships shape meaning, behaviour, and emotional regulation across the lifespan? And how can professionals support change without forcing insight, pathologising difference, or overlooking context?  A Clinical Guide to Interpersonal Constructs and Attachment Theory (ICAT) offers a powerful and integrative framework for understanding human behaviour as relational, adaptive, and deeply contextual. Bringing together attachment theory, constructivist and constructionist philosophy, and personal and systemic construct psychology, ICAT reframes distress not as deficit or disorder, but as a meaningful response to lived relational experience. Rather than treating attachment patterns, emotional reactions, or entrenched beliefs as problems to be corrected, ICAT understands them as intelligible strategies developed in response to safety, danger, culture, neurobiology, and power. Across theory and practice, the book demonstrates how attachment strategies, interpersonal constructs, affect regulation, and context interact in ongoing relational loops that shape how individuals anticipate, interpret, and respond to others. Central to ICAT is the proposition that safety precedes reflection , that patience can be a therapeutic act, and that relationship-not technique-is the primary medium of change. The model resists manualised intervention and instead offers a relational stance grounded in attunement, containment, ethical restraint, and reflective flexibility. Drawing on rich case material from therapy, education, social care, early years, residential settings, adult learning, and migration contexts, the book illustrates how ICAT can be applied across systems and across the lifespan. Alongside examples of effective practice, it includes reflective questions and ethically focused "what went wrong" cases that highlight the limits of relational work and the importance of context, timing, and power. Written for therapists, psychologists, educators, social workers, and relational practitioners, this book is a humane and ethically grounded guide for those who believe that meaningful change does not arise through pressure or perfection-but through safety, understanding, and time.