More than 250 babies are born every minute, while 150,000 people die daily with population increasing by almost three humans per second. Each of these people lives, thinks, worries, mourns, and daydreams with, and within, a very complex but marvellously organised body. Such a system is influenced by its environment and is able to adapt itself to constructive and destructive waves of changes in a continuously varying earth. To understand the structure and functions of the human body and to understand various biological and biochemical processes involved in human physical and mental development, not only the physiology of the organs but also their functions and perhaps their metabolic activities have to be studied. Most of these studies are done with the help of physiological and biological signs and symptoms measured from the human body invasively or noninvasively, by a variety of sensors and instruments developed through the years. These measurements can be in the form of time series of electric potentials from brain and muscles, images of different modalities, image sequences, heart and lung sounds, blood pressure, eye pressure, body temperature, skin impedance, enzymes, statistics, and many other biometrics. The systems for measuring such information have been improved in recent years, in light of the advances in science and technology. In parallel with the development of new measurement tools and systems, many mathematical and signal processing algorithms have also been introduced and implemented. With the help of such new achievements, diagnosis, treatment, and monitoring of diseases have become much easier, and more lives are saved.