With contributions by leading theoreticians, this book presents the discoveries of hitherto hidden connections between seemingly unrelated fields of fundamental physics. The topics range from cosmology and astrophysics to nuclear-, particle- and heavy-ion science. A current example concerns the sensitivity of gravitational wave spectra to the phase structure of dense nuclear and quark matter in binary neutron star collisions. The contributions by Hanauske and Stoecker as well as Banik and Bandyopadhyay relate the consequent insights to hot dense nuclear matter created in supernova explosions and in high-energy heavy-ion collisions. Studies of the equation of state for neutron stars are also presented, as are those for nuclear matter in high-energy heavy-ion collisions. Other reviews focus on QCD-thermodynamics, charmed mesons in the quark-gluon plasma, nuclear theory, extensions to the standard general theory of relativity, new experimental developments in heavy ion collisions and renewable energy networks. The book will appeal to advanced students and researchers seeking a broad view of current challenges in theoretical physics and their interconnections.