The notion of transdisciplinary science and technology has been gradually formed duringstruggles to establish the recognition of non-natural scientific foundation of engineering. This articlepresents the way the struggle has been conducted in the author’s step-by-step advance towardsthe understanding of transdisciplinary science and technology. Similar notions related to transdisciplinaryscience and technology, such as “pure engineering” and “design sciences”, are discussed inthe context of engineering education and social relevance of science and technology. The importanceof the transdisciplinary science and technology in the future techno-society is discussed. Consilienceof knowledge is discussed in the light of transdisciplinary science and technology.