Advances in ultraprecision diamond turning have revolutionized manufacturing processes across various industries, offering unparalleled precision and surface quality in the fabrication of optical components, microfluidic devices, and advanced mechanical parts. This review delves into the techniques, applications, and future trends in ultraprecision diamond turning, highlighting recent advancements and potential trajectories. Techniques in ultraprecision diamond turning have evolved significantly, driven by innovations in machine design, tooling materials, and control systems. Diamond turning machines equipped with ultra-stiff structures, high-speed spindles, and advanced feedback mechanisms enable sub-nanometer level accuracy and surface finishes down to Angstrom levels. Additionally, advancements in single-point diamond turning (SPDT), fast tool servo (FTS), and deterministic microgrinding (DMG) techniques further enhance the versatility and precision of the process. Applications of ultraprecision diamond turning span a wide range of industries, including aerospace, automotive, biomedical, and telecommunications. In optics manufacturing, diamond turning facilitates the production of aspheric lenses, freeform optics, and diffractive optical elements with unprecedented accuracy, contributing to the development of high-performance imaging systems and laser applications. Moreover, in the biomedical field, diamond-turned microfluidic devices enable precise control over fluid flow and particle manipulation, empowering advancements in drug delivery systems and lab-on-a-chip technologies. Future trends in ultraprecision diamond turning are poised to address challenges related to scalability, multi-material processing, and in-situ metrology. Integration of adaptive control algorithms and machine learning techniques promises enhanced process stability and predictive maintenance, optimizing productivity and reducing downtime. Furthermore, the development of hybrid manufacturing approaches, combining diamond turning with additive manufacturing or laser processing, offers novel avenues for fabricating complex, multi-functional components with improved efficiency and cost-effectiveness. The ongoing advancements in ultraprecision diamond turning techniques, coupled with diverse applications across industries, underscore its pivotal role in advancing manufacturing capabilities. Anticipated future trends hold promise for further expanding the scope and impact of this technology, driving innovation and pushing the boundaries of precision engineering.
 Keywords: Ultraprecision, Diamond, Turning, Technique, Review.