The genetic makeup of an organism is the foundation for its existence; as such, naturally occurring changes in this makeup result in evolution, adaptation, diversity, or sometimes genetic defects and disease. Methods and molecular tools used to introduce changes to this genetic makeup (for the purpose of understanding the role of genes and to modulate their functions) have been growing since the discovery and isolation of DNA. This purposeful genetic manipulation has accelerated and emerged as a distinct field of science known as genetic engineering. Therefore, genetic engineering simply refers to genetic modification in process and application. In this collection, we aim to collect relevant process methods such as (1) recombinant DNA and cloning, (2) genome editing, and (3) delivery techniques including viral vectors. Since the application of genetic engineering is ever-expanding in very diverse fields (including medicine, agriculture, and marine biology), we will limit the applications in this collection to gene therapy in medicine. Methods in this collection may include a new approach or modified version of an existing technique that imparts significant improvement(s) such as (1) cost, (2) accuracy, (3) speed, (4) quality, or (5) efficiency. Examples of acceptable methods include: (1) PCR-based technologies (2) DNA mutagenesis and gene editing techniques including traditional site-directed, TALEN, and CRISPR/cas9 (3) introduction of genetic materials into cells, organs, or organisms such as transformation and transduction using chemical, viral or non-viral vectors, and (4) methods identifying new molecular tools or functions such as enzymes, plasmids, probes, and tags.