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