Volume 5, Number 1, 2004Contents: R.S. Siegler, U-Shaped Interest in U-Shaped Development--And What It Means. L. Gershkoff-Stowe, E. Thelen, U-Shaped Changes in Behavior: A Dynamic Systems Perspective. L.L. Namy, A.L. Campbell, M. Tomasello, The Changing Role of Iconicity in Non-Verbal Symbol Learning: A U-Shaped Trajectory in the Acquisition of Arbitrary Gestures. C.H. Cashon, L.B. Cohen, Beyond U-Shaped Development in Infants' Processing of Faces: An Information-Processing Account. C.J. Brainerd, Dropping the Other U: An Alternative Approach to U-Shaped Developmental Functions. A. Demetriou, A. Raftopoulos, The Shape and Direction of Development: Teleologically but Erratically Lifted Up or Timely Harmonious? D.H. Feldman, A.C. Benjamin, Going Backward To Go Forward: The Critical Role of Regressive Movement in Cognitive Development. M. Friend, On the Implications of Curvilinear Trajectories for Cognitive Development. S. Goldin-Meadow, U-Shaped Changes Are in the Eye of the Beholder. S. Marcovitch, D.J. Lewkowicz, U-Shaped Functions: Artifact or Hallmark of Development? G.F. Marcus, What's in a U? The Shapes of Cognitive Development. D. Muir, S. Hains, The U-Shaped Developmental Function for Auditory Localization. C.A. Nelson, What Do Studies of Face Processing Tell Us About Trajectories of Development? A Commentary on Cashon and Cohen. T.T. Rogers, D.H. Rakison, J.L. McClelland, U-Shaped Curves in Development: A PDP Approach. J.F. Werker, D.G. Hall, L. Fais, Reconstruing U-Shaped Functions.