Book excerpt: A Dynamic Systems Approach to Development explores the value of dynamical systems principles for solving the enduring puzzles of development, including the ultimate source of change, the problems of continuity and discontinuities, and nonlinear outcomes and individual differences. What do laser lights, crystals, walking, reaching, and concepts have in common? All are complex dynamic systems. Over the last decade, the burgeoning fields of synergetics and nonlinear dynamics have shown in mathematically precise ways how such complex systems can produce emergent order from the cooperation of many simpler elements. A Dynamic Systems Approach to Development explores the value of dynamical systems principles for solving the enduring puzzles of development, including the ultimate source of change, the problems of continuity and discontinuities, and nonlinear outcomes and individual differences. This companion volume to the forthcoming A Dynamic Systems Approach to the Development of Cognition and Action shows how the ideas of dynamic systems may form the basis for a new theory of human development. The problems considered include areas of motor development, perceptual and cognitive development, and social development. The use of dynamic systems ranges from the metaphorical to the rigorously mathematical, but in all cases the contributions present a step forward in developmental theory.