It happens rarely that an individual is capable of pioneering work in several fields. Hermann Weyl was just such an individual, a profound thinker of wide intellectual range, a giant of our times. His vision was unique and penetrating not only in mathematics, but also in mathematical physics and in philosophy of science. Humanity, compassion and a powerful sense of the beautiful were the hallmarks of his personality and characteristic of his intellectual endeavour. The sheer range of his genius and his persistent search for a harmonious, intelligible architecture of the physical universe at once links him to the last great universalist mathematicians and thinkers of the nineteenth century such as Hilbert and Poincaré, and stands as a promise and anticipation of the future development of science and mathematics.