This is a non-technical introduction two the two pillars of 20th century physics: the Theory of Relativity and Quantum Mechanics. It presents a conceptual and philosophical discussion without entering the realm of complicated mathematics, focusing on natural sciences in general, and physics in particular.

The Einstein Papers Project was established in 1986 to assemble, preserve, translate and publish papers selected from the literary estate of Albert Einstein (more than forty thousand documents) and from other collections (more than fifteen thousand Einstein-related documents). In the first two decades of the Einstein Papers Project, the Princeton University Press has published ten of the projected twenty five volumes in the series, The Collected Papers of Albert Einstein. Introductions, headnotes, footnotes, etc., are provided in English, while all documents in the series are reproduced in the language in which they were originally written. The Press simultaneously publishes English translations of previously untranslated documents when it releases each volume in the series. This volume presents important new material on the young Einstein. It includes many previously unpublished documents, e.g. class notes for Heinrich Friedrich Weber's lectures on thermodynamics and electromagnetism during Einstein's second year at ETH Zurich, etc. Published by Princeton University Press

"This is how I was lead to the idea of time. Here is where a surprise was waiting for me". With these terms Henri Bergson (1859-1941) describes the discovery all his cogitation grew out of: the "durée", the simple fact – that many deny – that "time lasts". In the intellectual landscape of the end of the 19th century, which was characterized by a huge leap in the development of the exact sciences and in the spreading of Kant's philosophy, Bergson's iteration sounded like defiance.

The Philosopher Henri Bergson (1859-1941) creator of the "durée" theory was once asked to explain his premise concisely. The philosopher replied: "What I said was that time exists and is not a "space"". Differentiating between time of real existence -"durée" – and the "space" like time. Bergson meant that the real time has a novel unexpected quality, and cannot be anticipated due to unceasing creativity. Quantifiable time – physics time – on the other hand, all that transpires can be set in advance with the assistance of Mathematical Computations. If so the 'physical time' does not differ greatly from the 'space time' and the result of every movement in it can be calculated precisely in advance provided that we have enough data for the calculation. Since by this assumption the "durée" was stripped of all the process science related areas, it is only natural that while trying to base his central idea, Bergson turns to investigate the two main reality spheres: the spiritual or mental sphere, and in this essay – the life sphere. This is the origin of the spiritual-vitalistic theory.