Eleftherios Papantonopoulos is Emeritus Professor in the Physics Department of the National Technical University of Athens. His research interests include the study of Lie Algebras and their applications to elementary particles phenomenology; applications of the AdS/CFT correspondence to Condensed Matter Physics; studies of Relativity and Cosmology in Supergravity and String theories; study of Black Hole solutions, their perturbations and construction of cosmological models in Modified Gravity Theories; Gravitational collapse and Gravitational Waves. For more than 20 years he has organized the biennial Aegean Summer School for postgraduate students and young researchers.Mavromatos Nikolaos is Professor of Physics at Kings College London. His research interests include Astro-particle Physics; Quantum Gravity and Dirichlet-Brane Phenomenology; Strings and Conformal Field Theory; Yang-Mills Gauge Theory; Low-dimensional gauge field theories and Supersymmetry; interdisciplinary research between Condensed Matter and Particle Physics.

• Exact Black Hole Solutions in Higher Order Scalar Tensor Theories.- Compact Objects in Einstein-scalar-Gauss-Bonnet Theory and Beyond.- Dynamics of Scalarization.- Effective Field Theory Approach to Black Hole Scalarization and its Compatibility with Cosmic Evolution.- Conformal Renormalization and Energy Functionals in Anti de Sitter (AdS) Gravity.- Black Hole Spectroscopy: Quasinormal Modes, Ringdown Stability and the Pseudospectrum.- Huge WKB Method and Quasinormal Modes of String-Theoretical D-Dimensional Black Holes.- Spacetime Geometry of Rotating Boson Stars and KBHsSH.- Seven Years of LIGO-Virgo Science.- Astrophysics of Radio sources: Analysis of 21cm Post-Reionization Signals and Modeling of FRBs as PBHs with Magnetic Fields.- BINGO-ABDUS: A Radiotelescope to Unveil the Dark Sector of the Universe.- Machine Learning Applications in Gravitational Wave Astronomy.- Features in the Inflaton Potential and the Spectrum of Cosmological Perturbations.