This chapter explores the growing field of non-invasive brain stimulation (NIBS) techniques, highlighting their potential as effective therapeutic options that avoid the need for surgery. These techniques, which include transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), are explored for their unique mechanisms and applications in modulating neuronal activity. Through a detailed examination of each method, this chapter highlights their potential to influence brain oscillations, enhance cognitive functions, and treat a variety of neuropsychiatric and neurological conditions. Special attention is given to the scientific principles underlying each technique, their clinical implications, and the potential for inducing long-term changes in the brain. The discussion is anchored in the latest research findings and enriched with illustrative diagrams and case studies to provide a comprehensive overview of current capabilities and future directions in NIBS. The overarching goal of this chapter is to underscore the transformative potential of these technologies in advancing brain research and therapy, setting the stage for their expanded use in clinical settings.