Recombinant DNA–driven transformative innovations outlined in this volume trace the scientific, technological, and methodological evolution of genetic engineering across plant biotechnology, biosensor development, molecular diagnostics, food science, and cell-free synthetic biology. The chapters collectively emphasize how recombinant DNA methodologies enable the precise isolation, modification, transfer, and expression of genetic material, supporting applications ranging from Agrobacterium-mediated plant transformation to high-throughput biosensor-based selection strategies, CRISPR-enabled diagnostic platforms, and metabolic pathway optimization. Within plant sciences, recombinant DNA technology is shown to enhance crop resilience, productivity, and nutritional value through targeted gene transfer systems that exploit both vector-mediated and direct transformation approaches. High-throughput biosensor technologies are presented as critical tools for screening large genetic libraries, improving enzyme engineering, accelerating biopharmaceutical discovery, and enabling real-time metabolic monitoring within synthetic biology frameworks. CRISPR-based molecular diagnostics are examined as paradigm-shifting systems offering high specificity, rapid detection, and adaptability for infectious diseases and genomic surveillance. In food science, recombinant approaches underpin innovations in food safety, functional food development, and microbial engineering. Cell-free synthetic biology further expands the capabilities of recombinant systems by enabling decentralized, controllable biochemical production without living cells. Across these domains, the book highlights methodological convergence—automation, microfluidics, AI-assisted analytics, and genetically encoded sensors—which collectively drive precision, scalability, and sustainability. The work contributes to the biotechnology literature by integrating foundational molecular principles with contemporary applications, offering a multidisciplinary perspective on how recombinant DNA research shapes modern agriculture, medicine, and industrial biosciences.