The upheaval in quantum theory in the mid-1920s is often presented as a paradigm shift in the sense of Thomas S. Kuhn’s The Structure of Scientific Revolutions (1962). The new quantum mechanics, to use a building metaphor, was erected on the ruins of the old quantum theory, brought down by an accumulation of anomalies. In our book Constructing Quantum Mechanics (2019/2023), Tony Duncan and I use a different building metaphor. As suggested by the subtitles of the two volumes of our book, The Scaffold: 1900–1923 and The Arch: 1923–1927, we see the architects of the new quantum mechanics using parts of the old quantum theory as scaffolds to build the arch of the new one. In this talk, after sketching the underlying alternative to Kuhn's account of scientific revolutions in general, I will give an overview, as non technical as possible, of the genesis of quantum mechanics in the period 1900–1927. (Drawings by
Laurent Taudin. Based on joint work with Anthony Duncan of University of Pittsburgh).