A comprehensive account of the structural classes of antibiotics that have impacted human infectious disease.* Provides an introduction to antibiotics and examines how antibiotics block specific proteins acting in essential bacterial processes and how the molecular structure of the small-molecule drugs enables their antibiotic activity. * Explores the development of bacterial resistance to antibiotics, including the molecular logic that microbial producers of antibiotics use for self-protection. * Addresses the molecular logic of antibiotic biosynthesis, starting with regulatory networks that control gene transcription of secondary metabolites in streptomycetes, and examines the prospects for broadening the base of bacterial targets and also where new antibiotics are likely to emerge, including both synthetic chemical efforts and natural products.