Written by researchers who have helped to found and shape the field, this book provides an introduction to geometric modelling. The authors present a broad base of fundamentally important techniques for curve and surface representations in computer-aided modelling with a focus on how the techniques can be used in design. In achieving a balance between mathematical rigour and broad applicability, they show how theoretical properties can be harnessed to practical algorithms, how a somewhat more abstract treatment can occasionally provide unifying elegance and implement a rational advantage.