The purpose of this volume of Methods in Molecular Medicine is to set forth examples of the great variety of techniques and applications that are now emerging in the field of nonviral gene therapy. The book emphasizes not only specific approaches to gene delivery but, in particular, the best current me- ods to prepare, handle, and characterize gene delivery agents. These topics are of very broad importance since gene therapy evolves from its mostly ac- emy-based experimental and clinical research to the ever increasing number of industry-driven programs directed toward commercial development. S- cessful introduction of nonviral gene therapy agents into the clinic should be expected to require rigorous manufacturing and analytical methods that readily meet the regulatory guidelines under which new drug candidates are reviewed for marketing approval. Exactly what those guidelines will prove to be c- tainly depends on the established guidelines for review of both biological and chemical therapeutics. Additionally, many new techniques are being devised and applied to gene therapy research; these techniques will be instrumental in developing and characterizing successful gene delivery agents. Nonviral Vectors for Gene Therapy: Methods and Protocols has two main sections. To start with, there is a series of chapters on specific protocols for the synthesis, characterization, and application of gene delivery agents. S- eral chapters address the topic of materials to bind with DNA to form the compact condensed phases that facilitate cellular delivery.