The Second Quantum Revolution the breathtaking development of modern quantum science would not have been conceivable without the groundbreaking and Nobel-prize- winning contributions from Austria, such as quantum teleportation or the proposal of a trapped-ion quantum computer. These contributions are the basis on which quantum technologies are now being developed that surpass classical technologies in many areas. It is expected that they will revolutionize precision measurements, telecommunications, and above all the computation and simulation of complex many-body quantum systems, which are at the heart of important technological problems ranging from biomolecules to quantum materials. While scientists are learning more and more about the use of quantum physics, other fundamental phenomena, especially in cosmology, still lack a conclusive explanation. Even though the physics of gravity and that of quanta are well understood in their own right, there are no descriptions of phenomena where both areas have strong influences. For example, no one currently knows what is really going on inside a black hole. To solve these essential questions a much better fundamental understanding of complex quantum processes is needed. The central goal of the Cluster of Excellence Quantum Science Austria, is to expand the frontiers of knowledge in quantum science and thus to be a driver for future innovations. The focus is on fundamental questions about the quantum nature of space, time and gravity, new paradigms in quantum information science and the physics of quantum many-body systems. The scientists in Innsbruck, Vienna, Linz and Klosterneuburg ask innovative questions that can only be solved by combining the unique know-how available in Austria. Using world- leading theoretical methods and precisely controlled model systems based on trapped ions, ultracold atoms, long-range interacting systems, superconducting quantum circuits, and nanoscopic solid-state systems, they aim to unravel the most difficult mysteries of the quantum world. With their advanced solutions, they will prepare the ground for the next generation of quantum technologies. An intensive training program will educate the quantum scientists of the future, who will make these technologies ready for practical applications.