Synchronous machines (SMs) are pivotal in applications that demand high-performance operations, where their efficiency largely hinges on torque control. This paper delves into the current advancements in SM control technologies and emphasizes optimal torque control strategies. It outlines methodologies for addressing the optimal torque control problem and the acquisition of crucial SM parameter information. Moreover, the paper highlights novel approaches and significant findings in enhancing torque control performance, thus setting the stage for future research directions. The discussion extends to upcoming trends and pivotal technologies that are poised to shape the future of SM torque control.