This volume details the transport of molecules, large and small, across the membranes of prokaryotic and eukaryotic microbial cells. An international group of contributors unify a diverse range of phenomena with the discussion of the signal peptides that target proteins to particular destinations, and the role of chaperonins. Topics covered include secretion of proteins out of the bacterial cell by Type I, II, and III mechanisms, including the newly recognized bacterial signal recognition pathway in Type II; passage across internal membranes of eukaryotic proteins, whether destined for secretion or en route to internal organelles such as chloroplasts and peroxisomes; how bacteria obtain energy required for solute uptake; the role of phosphorylation and evolutionary relationships of the proteins involved; and efflux pumps for toxic substances in bacterial, animal, and plant cells.