This chapter provides a detailed reference for X-ray tube technology, starting from its evolu-tion from Wilhelm Conrad Röntgen’s foundational discovery to the sophisticated innova-tions of the 21st century. The historical explains from early Crookes tubes and thermionic cathodes to the introduction of rotating anode technology, liquid metal bearings, and microbeam radiotherapy-capable X-ray tubes. Each innovation is provided with its contribution to improving the image quality, efficiency, and clinical utility. A detailed discussion follows on the components essential to X-ray generation, including the cathode and anode assemblies, focusing cups, target angles, heat dissipation systems, and both glass and metal-ceramic envelopes. The structural and functional elements of tube housing assemblies such as lead shielding, high-tension cable sockets, and stator coils are elaborated, along with design strat-egies to ensure thermal stability, beam collimation, and patient safety. The chapter further classifies X-ray tube types, distinguishing between stationary and rotating anode tubes, and elaborates on their specific applications, advantages, and limitations. Special tube designs used in dental, mammography, fluoroscopy, interventional imaging, and micro- and nano-focus applications are discussed in context. Finally, the chapter addresses X-ray generator systems, exposure controls, common tube failures, maintenance protocols, and recent technological advances aiming to extend the tube life, enhancing resolution, and reducing patient radiation dose.