This book suggests a new model of elementary particle physics based on a priori ontology known as apriorics. Although this theory does not use any free parameters and includes only five basic principles, it has a significant predictive power and its findings substantiate the Standard Model of elementary particle physics. This book is mainly designed for researchers, including graduate students interested in the philosophical aspects of physics. However, owing to the simplified presentation of the concepts, ideas and framework of the suggested theory, it may also expand the horizons of undergraduate students in physics, mathematics and philosophy, and teachers of these fields as well in high schools and colleges.