What shapes human behavior? Christopher Hudson approaches this conundrum with an outstanding grasp of the theoretical underpinnings of the human services. In this penetrating new book, Hudson guides us through the common roots of social work and psychology with authority and lucidity to revisit the richness of human experience. Particularly notable for its integrative style, the book offers a comprehensive overview of the many theories that underlie contemporary social work practice, all carefully interpreted through the lens of complex systems theory. Hudson evaluates concepts like deep ecology, chaos theory, consciousness, diversity, and spirituality with clarity and enthusiasm, placing them in historical and theoretical contexts. His incisive review of the work of major thinkers from Comte, Freud, and James, through Vygotsky, Baars, and Varela, will help bring his readers to a more complex view of the human condition. An excellent book for all human services practitioners as well as advanced students of human behavior, Complex Systems and Human Behavior is a comprehensive introduction to complex systems theory and a necessary resource for all who seek a greater understanding of the evolution and foundation of their craft.