For bacteria ..."the times are achanging"... The genomes of over 60 different bacteria have now been sequenced, and we know a lot about the important research organism Escherichia coli, the important industrial organism Bacillus subtilis, and about important plant and human pathogens. It will not take long before we know all the gene products and their functions of a few of these bacteria. Some of us already begin to think about a digital model E. coli or Bacillus cell. For that end we need to know all the physiological activities and metabolic routes of the cell. But in addition we like to know how things work at the molecular level and how protein and membranes as well as other (macromolecular) structures work together to carry out specific cell functions. Protein Secretion Pathways in Bacteria describes all the known folding and targeting routes of inner and outer membrane proteins as well as of proteins that are secreted by several specific export routes. The book gives detailed molecular information about the structures that are important for the different mechanisms involved. This is a valuable contribution to the understanding of how rather simple and yet complex bacterial cells work.