With the spread of COVID-19, Mathematical Biology has gained significant prominence not just among the scientific community but also population-wide. This volume is a collection of state-of-the-art research on this subject. Infectious diseases are highlighted in this volume with novel results on the Zika-dengue interactions, malaria-HIV interactions, and cholera, which in the last decade were the causes of problems in public health.Readers will find chapters that address novel mathematical techniques for studying infectious disease models, such as methods for deriving the basic reproduction numbers in reaction-diffusion epidemic models, and methods for studying epidemic models on networks. Several chapters are focused on population dynamics and ecological interactions. Here novel techniques for approximation of stochastic population processes have been developed and types of predator-prey models have been established and investigated.Cancer is one of the non-infectious killer diseases of the 21st century. The chapters here study angiogenesis and angio-genesis therapy and apply optimal control to the tumor-immune interaction model.