This volume contains the proceedings of two conferences. The first part covers "The Non-Sleeping Universe: Stars and the ISM", and has activity as the underlying theme. It reviews the 1990s status of astroseismology, stellar rotation and activity. Highlights include the time behaviour of phenomena related to activity, both in the case of the Sun and of its much younger analogues, in view of the results of space missions. It also examines the diagnostic tools and the models, once again for the Sun and young low mass stars, including the jets and flows closely associated with those stars during the extreme phases of pre-main-sequence evolution. The second part comprises "The Non-Sleeping Universe: from Galaxies to the Horizon". It covers topics ranging from high energy phenomena on galactic scales, such as gamma-ray bursts, active galactic nuclei and intense periods of star formation, to competing models which attempt to explain the formation of large-scale structures in the Universe.It also addresses the theory of fluctuations in the cosmic microwave background radiation and their present observational status, together with the connection between the evolution of the number density of galaxy clusters with time and the present value of the matter density in the Universe.
