Protein translocation across the endoplasmic reticulum membrane / Ramanujan S. Hegde -- Preprotein translocation through the sec translocon in bacteria / Antoine P. Maillard, Kenneth K.Y. Chan, and Franck Duong -- Protein translocation in archaea / Jerry Eichler -- Structure of the SecYEG protein translocation complex / Ian Collinson -- Membrane protein insertion in bacteria from a structural perspective / Mark Paetzel and Ross E. Dalbey -- The twin-arginine transport system / Frank Sargent, Ben C. Berks, and Tracy Palmer -- Retro-translocation of proteins across the endoplasmic reticulum membrane / J. Michael Lord and Lynne M. Roberts -- Chloroplast protein targeting: multiple pathways for a complex organelle / Matthew D. Smith and Danny J. Schnell -- The mitochondrial protein import machinery / Doron Rapaport -- Import of proteins into peroxisomes / Sven Thoms and Ralf Erdmann.