This book develops an Effective Theory of Quantum Gravity based on the two pillars of physics - namely, General Theory of Relativity and Quantum Mechanics. It opens up a new direction of research in the search for a quantum theory of gravity, by first exactly quantizing the Newton-Cartan-Schrodinger theory of non-relativistic gravity, and then special relativizing the quantized theory by invoking Mach's Principle in the case of the universe and Schwarzschild radius in the case of massive stars and black holes. The main technique employed for the latter task is a variational technique using a trial local density. Subodha Mishra is a Professor of Physics at the Institute of Technical Education and Research, Bhubaneswar, India. He has two doctoral degrees in Physics; one from University of Missouri-Columbia, USA, and the other from Institute of Physics, India. His research interests are in theoretical physics; especially in theoretical condensed matter physics and cosmology.Joy Christian is a Researcher at the Department of Physics and Wolfson College of the University of Oxford, UK. He received his doctoral degree in Foundations of Physics from Boston University, USA, and has been a Visiting Professor at the Perimeter Institute for Theoretical Physics, Canada. His main research interests are in the foundations of quantum and gravitational physics, with an outlook towards a theory of quantum gravity.