The Human Genome Project continues to reveal the genetic basis for numerous acquired and inherited diseases ranging from cancer, HIV, and heart disease to muscular dystrophy and hemophilia. With this wealth of information, the ability to design patient-specific drugs that alter the cellular machinery at the genetic level in a way that controls or treats a specific disease will increasingly become a reality. Designing nucleic acid drugs as well as engineering novel delivery vehicles that encapsulate and effectively transport genetic materials into cells provides an opportunity to enhance the understanding of disease mechanisms and may help treat or cure these diseases. This issue of MRS Bulletin on “Designer Materials for Nucleic Acid Delivery” explores the diverse materials—polymers, lipids, nanoparticles, biocompatible scaffolds, and engineered peptides—that are being evaluated for the intracellular delivery of nucleic acids. These synthetic delivery systems are actively being investigated for many research purposes that range from gene-based therapy, genetic vaccine, and RNA interference to gene function and cellular signaling studies. This area is currently being pursued by a broad group of academic, clinical, and industrial researchers at both the fundamental and applied level, motivated by the widespread implications for human health. In this introductory article, we provide a general tutorial to gene-based therapies and a brief overview of the many areas of materials research that are currently making a tremendous impact on this interdisciplinary field.We conclude with a discussion of the future challenges that materials researchers face in developing viable nucleic acid delivery vehicles.