The spectacular advances of medicinal chemistry in the last few decades have been triggered by a greater understanding of cellular processes at the molecular level. The understanding of biochemical processes and diseases at molecular level has revolutionized the field. This volume summarizes recent developments in the area of biological inhibitors such as squalene epoxidase inhibitors, dual inhibitors of 5-lipoxygenase and cycloxgenase, inhibition of cholestrol biosynthesis, HIV proteinase inhibitors, nonpeptide antagonists at peptide receptors, and binding interaction of thyroid hormones.