Quantum Cosmology

'Quantum Cosmology' offers a guided introduction to the quantum aspects of the cosmos. Starting with an overview of early universe cosmology, the book builds up to advanced topics such as the Wheeler-DeWitt equation, gravitational path integrals, and the no-boundary proposal for the wave function of the universe. Readers will explore tunneling processes via Coleman-DeLuccia instantons, the quantum origin of primordial fluctuations, the thermodynamics of horizons, and basic notions of string cosmology. Concepts such as wormholes and semi-classical geometry are introduced with clarity and physical motivation. The book assumes some familiarity with general relativity and quantum mechanics, but little prior knowledge of cosmology. It includes a wide range of exercises, with solutions provided. Written in a pedagogical style, it bridges the gap between undergraduate courses and the research level in this frontier area of theoretical physics.