This volume is dedicated to Jirí Bičák on the occasion of his 60th birthday. The authors are his former students who currently work in the fields of general relativity, astrophysics, theoretical physics and cosmology. Unlike in traditional Festschrifts with many short contributions, they present several comprehensive surveys and elaborate original works. The subjects range from the motion of stars in galactic nuclei to quantum mechanics on a boundary, and include current topics such as cosmological perturbations, effects of a repulsive cosmological constant, discs around black holes and gravitational waves. An unconventional introductory essay revives Prague's inspirations as personified by Tycho Brahe, Johannes Kepler, Christian Doppler, Ernst Mach, Albert Einstein and others.