Basic Aspects.- 1 The Epidermal Barrier and Strategies for Surmounting It: An Overview.- 2 Stem Cells, Differentiation and Renewal Kinetics of Keratinocytes: Implications for Cutaneous Gene Therapy.- 3 Relevant Animal Models for Skin Gene Therapy.- 4 Nonviral Gene Transfer into the Skin.- 5 Safety and Pharmacokinetics of Naked Plasmid DNA: Studies on Dissemination and Ectopic Expression.- 6 Uptake of DNA by Keratinocytes.- Treatment of Skin Diseases.-...