The book addresses fundamental conceptions in quantum mechanics. Its point of view goes from the classical to the quantum and back, taking the reader into a constant reviewing of the formulations, interpretations, and common misinterpretations in quantum physics. It has a good emphasis in the experimental grounds of the origins of quantum physics. The ontological and epistemological discussion related to quantum mechanics interpretations follow some of the recent approaches, giving a fresh review of the current state in the field.