This chapter provides a comparative overview of various noninvasive brain stimulation (NIBS) techniques, including Transcranial Magnetic Stimulation (TMS), Transcranial Direct Current Stimulation (tDCS), Transcranial Alternating Current Stimulation (tACS), and Deep Brain Stimulation (DBS). It explores these methods’ distinct mechanisms, applications, and comparative efficacy in clinical and research settings. This chapter explores key theories like Network Modulation and Neuroplasticity, which form the basis for how these technologies affect neural activity and deliver therapeutic benefits. It also highlights the essential steps in designing and conducting brain stimulation studies, focusing on choosing the right stimulation parameters and accounting for individual differences in brain structure and function. Applications of brain stimulation across various neurological and psychiatric disorders are examined, highlighting its potential for enhancing cognitive functions and treating refractory conditions. This chapter concludes by considering future directions in brain stimulation research, including the integration of advanced imaging techniques and real-time feedback systems to enhance the specificity and efficacy of these interventions. This synthesis of current knowledge and emerging trends underscores the growing significance of brain stimulation in neuroscience and medicine, offering promising avenues for both understanding and treating complex brain disorders.