This detailed volume explores perspectives and methods using cell-free expression (CFE) to enable next-generation synthetic biology applications. The first section focuses on tools for CFE systems, including a primer on DNA handling and reproducibility, as well as methods for cell extract preparation from diverse organisms and enabling high-throughput cell-free experimentation. The second section provides an array of applications for CFE systems, such as metabolic engineering, membrane-based and encapsulated CFE, cell-free sensing and detection, and educational kits. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.