The popularisation of quantum mechanics, a worthwhile and arguably essential endeavour the scientific community is tasked with, has repeatedly lent the flank to ill-advised spectacularisation and pseudo-scientific mystification. This is not only a consequence of the theory's heavy reliance on an abstract and unintuitive mathematical formalism, which is difficult to put into words. It is also due to the fact that quantum mechanics, while successful in describing the experimental practice, is afflicted by a fundamental incongruity, the notorious "measurement problem", often disregarded or downplayed by both specialists and popularisers. Exactly one hundred years from the first complete formulation of quantum mechanics, and in the midst of the "second quantum revolution" spurred by the advent of quantum computing, this book aims at refocusing attention on the theory's inconsistencies, and on their philosophical implications. It does it by presenting a self-contained introduction to quantum mechanics without recurring to the mathematical formalism but also without compromising on rigour or fighting shy of controversial issues. Most interpretations of quantum mechanics, from the classic Copenhagen to the famous many-world, are also reviewed in the process. Alessio Serafini is a Professor of Theoretical Physics at University College London. He has published too many research papers, one graduate textbook (just the right amount), and too few philosophical rants, which is a pity, since that is where his heart truly lies.