Recent years have seen a considerable emphasis on growth factors and the elucidation of their mode of function, which has led to the recognition that growth factors, their receptors as well as downstream elements of signalling associated with their function might be potential targets in therapeutic management of human diseases. Humanised monoclonal antibodies raised against growth factor receptors have proved to be valuable for targeted cancer treatment and in patient management. This book reviews the latest developments providing insights into the signalling processes involved in morphogenesis and pathogenesis with emphasis on using the elements of the signalling cascades as targets for therapeutic deployment.