This book is about the epistemology of quantum physics and its interpretation as a scientific theory in its technical form. The contents of the book are essentially of non-formal nature although the formalism of quantum mechanics is also investigated (rather briefly) inline with the needs and requirements of the epistemological investigation and considerations. The reader should note that a general scientific and mathematical background (at the undergraduate level) is required to understand the book properly and appreciate its contents. The book is like my previous books in style and favorable characteristics (such as clarity, graduality and intensive cross referencing with hyperlinks in the electronic versions). However, the book, unlike my previous books, does not contain questions or exercises or solved problems. The book is particularly useful to those who have special interest in the interpretative aspects of quantum theory and the philosophy of science although it should be useful even to those who are interested in the purely-scientific and technical aspects of the quantum theory since the contents of the book should broaden the understanding of these aspects and provide them with qualitative and interpretative dimensions (as well as the added benefit of the brief investigation of the formalism of quantum mechanics).