This volume details protocols that cover the broad arsenal of techniques used to study a secretion system from A to Z. Chapters focus on identifying and localizing the different subunits, defining interactions within subunits, monitoring conformational changes, purifying and imaging of large complexes, defining the assembly pathway by fluorescence microscopy and the role of energy during assembly and/or secretion, identifying secreted effectors as well as reporters to follow effector transport. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Bacterial Protein Secretion Systems: Methods and Protocol aims to provide techniques that are not restricted to the study of secretion systems but arealso of specific interest for any researcher interested on multi-protein complexes of the bacterial cell envelope.