Analytical Modeling of Biosensors.- Biosensor Action.- Modeling Biosensors at Steady State and Internal Diffusion Limitations.- Modeling Biosensors at Steady State and External Diffusion Limitations.- Modeling Biosensors Utilizing Microbial Cells.- Modeling Nonstationary State of Biosensors.- Numerical Modeling of Biosensors.- Mono-Layer Mono-Enzyme Models of Biosensors.- One-Layer Multi-Enzyme Models of Biosensors.- Multi-Layer Models of Biosensors.- Modeling Biosensors of Complex Geometry.- Numerical Methods for Reaction-Diffusion Equations.- The Difference Schemes for the Diffusion Equation.- The Difference Schemes for the Reaction-Diffusion Equations.