Paul Andersen describes the defining characteristics of the domain Eubacteria. He begins with a quick description of the phylogeny of bacteria and horizontal gene transfer. He then surveys the structures of a bacteria; nucleoid region, capsule, pilli, cell wall with peptidoglycan, flagella. He describes the differing morphologies and metabolism in different bacteria. He describes how bacteria can be Gram positive or Gram negative. He finishes with a brief discussion of quorum sensing.