1. Introduction -- 2. Classes and applications of CPP -- 3. CPP selection, prediction and in silico analysis -- 4. Labeling of CPPs -- 5. Methods for CPP functionalization with oligonucleotides -- 6. Additional (gene therapeutic) platforms -- 7. Protein delivery and mimicry -- 8. General targeting strategies -- 9. Targeting specific barriers -- 10. Methods for molecular imaging, detection and visualization of CPPs -- 11. Methods for structural studies of CPPs -- 12. Kinetics -- 13. Toxicity and immune response -- 14. Cell-translocation mechanisms of CPPs -- 15. Clinical trials and commercialization using CPPs -- 16. Therapeutic potential of CPPs -- 17. CPP functionalized nanoparticles -- 18. Concluding remarks.