This volume brings together from several disciplines some of the recent developments in the nonlinear analysis of systems from biology and medicine and the noise effects on them. It contains a series of coordinated lectures on the topics of nonlinearity and chaos in neuronal and cardiac activity, chaos control, spatio-temporal dynamics, noise and stochastic resonance. The applications range from the noninvasive treatment of cardiac arrhythmias and epileptic foci to the development of new diagnostic and therapeutic techniques based on the stochastic resonance, to the defibrillation approach based on detailed spatio-temporal models, to the transfer of information in chaotic systems.