Computational and theoretical tools for understanding biological processes at the molecular level is an innovative area of science. Using these methods to study the structure, dynamics and reactivity of biomacromolecules in solution, computational chemistry is becoming an essential tool, complementing the more traditional methods for structure and reactivity determination. 'Modelling Molecular Structure and Reactivity in Biological Systems' covers three main areas in computational chemistry - structure (conformational and electronic), reactivity and design. Initial sections focus on the link between computational and spectroscopic methods in the investigation of electronic structure. The use of Free Energy calculations for the elucidation of reaction mechanisms in enzymatic systems is also discussed. Subsequent sections focus on drug design and the use of database methods to determine ADME (absorption, distribution, metabolism, excretion) properties.