Gross peptidoglycan structure and mechanisms of synthesis are conserved across all bacteria with differences arising in the amino acid composition of peptide side chains, the presence and composition of peptide cross bridges involved in cross-linking, lengths of glycan strands, and levels of acetylation and deacetylation of the glycan strands. Synthesis of precursor molecules utilized for polymerization of peptidoglycan strands takes place within the cell cytoplasm. Analysis of peptidoglycan synthesis in developing spores indicates that the germ cell wall is the first spore peptidoglycan synthesized and that its structure is stable through the remainder of spore development. The majority of the spore peptidoglycan, the cortex, appears to take place from the mother cell side of the inter-membrane space, being laid down in successive layers around the germ cell wall. Observations that cell wall autolysis is enhanced by ionophores or uncouplers have led to proposals that autolysins may be controlled by the proton motive force. Surface layers (S-layers) have been demonstrated to affect attachment of extracellular amylase to Bacillus stearoihermophilus, phage attachment to Lactobacillus helveticus, protection from predatory bacteria in Cauhbacter crescentus, and virulence of Campylobacter fetus. Assignment of capsule synthesis function to Cps14E genes must be made with caution, as some of these gene products also have significant similarity to proteins involved in anionic polymer synthesis or implicated in spore surface protein glycosylation. Recent studies have begun to elucidate important details of the chemical complexity of the cell wall and how it is synthesized, modified, and hydrolyzed.