Computer-aided drug design and in silico screening have contributed to the discovery of several compounds that have either reached the market or entered clinical trials. In silico Lead Discovery is a compilation of the efforts of several experts on bioinformatics and drug design in developing the latest advances of in silico approaches for lead discovery. It contains an overview of structure-based, ligand-based methods and current fragment-based methods as well as examples for successful applications of such methods in discovering new hit/lead molecules for important therapeutic targets. Treatment of receptor flexibility - which is one of the most important challenges for in silico screening today – has also been highlighted in the eBook. Biomedical scientists, biologists and chemists can find valuable information here that could help them to initiate or to complete chemical biology projects with the goal of designing new hit-to-lead molecules or chemical probes for chemogenomics projects.