Book excerpt: This book constitutes the refereed proceedings of the Second International Conference on Medical Image Computing and Computer-Assisted Intervention, MICCAI'99, held in Cambridge, UK, in September 1999. The 133 revised full papers presented were carefully reviewed and selected from a total of 213 full-length papers submitted. The book is divided into topical sections on data-driven segmentation, segmentation using structural models, image processing and feature detection, surfaces and shape, measurement and interpretation, spatiotemporal and diffusion tensor analysis, registration and fusion, visualization, image-guided intervention, robotic systems, and biomechanics and simulation.