The Poincare plot (named after Henri Poincare) is a popular two-dimensional visualization tool for dynamic systems due to its intuitive display of the dynamic properties of a system from a time series. This book presents the basis of Poincare plot and focus especially on traditional and new methods for analysing the geometry, temporal and spatial dynamics disclosed by the Poincare plot to evaluate heart rate variability (HRV). Mathematical descriptors of Poincare plot have been developed to quantify the autonomic nervous system activity (sympathetic and parasympathetic modulation of heart...