The major purpose of this thesis is to investigate some essential aspects of the teachings and philosophy of Maharishi Mahesh Yogi (1917-2008) expressed during different periods of time. There is a primary focus on the teachings expressed in Maharishi’s translation and commentary on the didactic poem, Bhagavadgītā, with extensive references to Maharishi’s metaphorical language. The philosophy and teaching expressed in this text is investigated in relation to later texts. Since maybe the most significant and most propagated message of Maharishi was his peace message, its theory and practice, as well as studies published regarding the so-called Maharishi Effect, are reflected in the thesis. Maharishi’s philosophy and teachings are analysed using three categories: 1. Vision and Tradition, as Maharishi could be considered on the one hand, a custodian of the ancient Vedic tradition and is associated with the Advaita Vedānta tradition of Śaṅkara from his master. On the other hand, Maharishi could be considered an innovator of this tradition and a visionary in his interpretation of the Vedic texts in relation to modern science. 2. Consciousness and Experience are central concepts in the teachings of Maharishi Mahesh Yogi, as well as the relationship between them, which is evidenced by their use in Maharishi’s writing and lecturing. 3. Practice before Theory is a concept used because of the numerous instances in Maharishi’s philosophy and teaching indicating that he put practice before theory for spiritual development. The practice of Transcendental Meditation and the advanced TM-Sidhi programme is according to Maharishi in his vision of a better society most essential and he considered the application of a practice forgotten in many interpretations of texts like the Bhagavadgītā. The thesis thus considers Maharishi’s view on “Veda” and the “Vedic literature”, and on the Self, Ātmā, which could be considered the single most important concept in Maharishi’s world of ideas on which his entire teaching is based.