The book "Respiration in Archaea and Bacteria" provides a comprehensive summary of the advances made in the last ten years in the fields of biochemistry, bioenergetics, and structural and molecular biology of respiratory processes in selected bacterial genera. It also thoroughly discusses the redox chains of extremophiles within the Archaea domain. The individual chapters highlight important microbiological and ecological aspects, such as the utilization of ammonium, iron, methane, sulfur, and hydrogen as respiratory substrates, as well as the role of nitrogen compounds in denitrification processes. Special attention is given to specific groups of prokaryotes, including gram-positive bacteria, acetic acid bacteria, and pathogenic genera such as Helicobacter and Campylobacter. The book is aimed at doctoral students, researchers, and students in the fields of microbiology, biochemistry, and ecology, serving as a long-term information source for fundamental and applied sciences, medicine, and agriculture.