Book excerpt: A concise, readable introduction to systems theory (and especially second-order cybernetics) with practical applications to family therapy. Systems Theory and Family Therapy: A Primer, Fourth Edition, provides a thorough yet concise explication of systems theory (cybernetics), which is the primary paradigm for the practice of systemic individual, marital, and family therapy. This book provides an overview of the essential concepts of a systems theoretical perspective using families and family therapy in context as examples and illustrations of their application in professional practice. Readers are invited to see themselves as parts of the systems with which they are working, consistent with a second-order cybernetics perspective. This book concludes with more than one hundred examples of how the meta-perspective of systems theory can be used in work with families.