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...