<p>This book discusses the numerical treatment of delay differential equations and their applications in bioscience. A wide range of delay differential equations are discussed with integer and fractional-order derivatives to demonstrate their richer mathematical framework compared to differential equations without memory for the analysis of dynamical systems. The new edition introduces advanced numerical techniques for solving pantograph-type DDEs, including stability analyses. The book also integrates recent research on stochastic models of DDEs, particularly from the fields of immunology and cancer modeling. In addition, the book includes updated case studies from biological and medical sciences, such as glucose-insulin interaction models and infectious disease dynamics. This book is particularly valuable to mathematicians, researchers, and professionals in the fields of mathematical biology, life sciences, immunology, and epidemiology.</p>