Systems of Biology and the Spirit of Tustin [Perspectives]

From a historical perspective, we are at a stage in science comparable to the post-Newtonian developments of physics, engineering and technology-with the key difference that now we are trying to create a solid quantitative mathematical basis for biology, physiology and the study of disease. The enormous complexity of living systems means that understanding their behaviour in a quantitative mathematical way is very difficult. However, a large element of the difficulty is associated with the complexity of the dynamical properties of biological systems. This means that the tools of control, feedback theory and dynamical systems analysis should be central to a systems approach to biology. It is of inestimable importance that today's generation of control systems engineers recognise this and respond, in the Spirit of Tustin, to the opportunities that it presents.