The biosynthesis of Beta-lactums. Structure-activity relationships: Chemical. Structure-activity relationships: biological. The mechanisms of reactions of Beta-lactams. Mode of action: interaction with the penicillin binding proteins. Beta-Lactamase: mechanism of action. Beta-Lactamase: inhibition. Novel Beta-Lactam structures-the carbacephems . Non-Beta-Lactam mimics of Beta-lactam antibiotics. Classical Beta-Lactam structures. Index.