The development of theoretical physics can be seen as a continuous improvement of the models of space and time. In particular, the beginning of the 21st century brought a new vision into quantum physics: quantum particles move in space only, time measured with clocks is merely a numerical order of particles' motion. This so called "a-temporal" view of physics offers a radically new understanding of the micro and macro universe. On the basis of the notion of time as numerical order of material change, in this book the authors introduce suggestive unitary and holistic perspectives in the interpretation and explanation of several physical phenomena of contemporary physics. It is shown that the concept of time as a mathematical quantity measuring the numerical order of material changes resolves Zeno problems on motion, hypothetical travel into past, twin paradox of special relativity and allow new perspectives to be opened in the interpretation and explanation of Einstein-Podolski-Rosen experiment and of non-local correlations between subatomic particles. Moreover, a timeless description of the gravitational interaction and the idea of a timeless three-dimensional quantum vacuum as a fundamental bridge between gravity and quantum behaviour of matter are developed. Finally, in the second part of the book, after analysing the fundamental features of some relevant unitary theories of contemporary physics (such as superstring theory and loop quantum gravity) and making some considerations about being versus becoming and atomism versus monism in modelling physical reality at a fundamental level, it is shown that the replacement of the concept of time with the numerical order of material change provides a new suggestive interpretation of the fundamental unitary field theories opening the doors to a real "timeless theory of everything". The use of a simple and fluid language makes the book accessible to a wide reading public.