chapter 1 The Tat-Derived Cell-Penetrating Peptide / chapter 2 Penetratins / chapter 3 Transportans / chapter 4 Model Amphipathic Peptides / chapter 5 Signal Sequence-Based Cell-Penetrating Peptides and Their Applications for Gene Delivery / chapter 6 Hydrophobic Membrane Translocating Sequence Peptides / chapter 7 Arginine-Rich Molecular Transporters for Drugs: The Role of Backbone and Side Chain Variations on Cellular Uptake / chapter 8 Interactions of Cell-Penetrating Peptides with Membranes / chapter 9 Structure Prediction of CPPs and Iterative Development of Novel CPPs / chapter 10 Biophysical Studies of Cell-Penetrating Peptides / chapter 11 Toxicity and Side Effects of Cell-Penetrating Peptides / chapter 12 Quantification of Cell-Penetrating Peptides and Their Cargoes / chapter 13 Kinetics of Uptake of Cell-Penetrating Peptides -- chapter 14 Signal Peptides / chapter 15 Cell-Penetrating Peptide Conjugations and Magnetic Cell Labels / chapter 16 Cell-Penetrating Peptides as Vectors for Delivery of Nucleic Acids / chapter 17 Protein Transport / chapter 18 Microbial Membrane-Permeating Peptides and Their Applications