The universe, in all its vastness and complexity, continues to challenge our understanding, demanding ever more refined theories and deeper insights. At the frontiers of physics, we stand on the precipice of discovery, attempting to reconcile the mysteries of black holes, cosmic strings, dark dimensions, and evolving physical constants into a coherent framework of cosmological physics. This book is a deep exploration of the cutting-edge developments in theoretical cosmology, providing an analytical lens on the most pressing questions of our time.