This book examines the synthesis, properties and biological activities of antibacterials. Chapter One focuses on the recent development of biomass antibacterials. Chapter Two provides comprehensive overview on smart materials based on structured noble metals covering its various forms from ultrathin layers over discrete metal islands up to isolated nanoparticles having exceptional properties applicable in prevention of bacterial infections. Chapter Three discusses general aspects regarding lectins and their purification and then reviews the state-of-art on antibacterial lectins, their action mechanisms, defensive roles and current efforts regarding their effective biotechnological application. Chapter Four reviews natural antibacterials for technical applications. Chapter Five studies antimicrobial activities of natural products from Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz var. ferrea. Chapter Six discusses redox-active metal complexes with cycloaminomethyl derivatives of diphenols. Chapter Seven analyzes recent progress in the discovery and development of novel antibiotics during the first fifteen years of the 21st Century.