B-splines are fundamental to approximation and data fitting, geometric modeling, automated manufacturing, computer graphics and numerical simulation. With an emphasis on key results and methods that are most widely used in practice, this book provides a unified introduction to the basic components of B-spline theory: approximation methods, modeling techniques and geometric algorithms. Topics discussed include the Bezier form; approximation and interpolation; error estimates; spline representations of curves, surfaces and solids; hierarchical bases; and finite element simulation. This book is ideal as an advanced undergraduate or first-year graduate text for courses on splines or approximation and geometric modeling for students in mathematics, engineering and computer science. A supplementary web site provides a collection of problems with selected solutions, slides for use in lectures, and programs with demos. This book also represents a valuable resource for practitioners whose work involves B-splines in the context of numerical simulations, computer-aided design, or visualization.