I have been trying to understand clearly the concept of non locality, hidden variables, quantum measurement etc through research papers. I also read Quantum Theory and measurment by Wheeler and Zurek but I feel I've got nothing into my head. Please recommend some introductory books on above mentioned topics for beginners.
Lectures on Quantum Theory: Mathematical and Structural Foundations by Chris Isham is a thin, easy to read book. The first 6 or so chapters are a simple introduction to quantum mechanics, but from about chapter 7 or 8 he goes into the Quantum Measurement problem and various interpretations and their associated difficulties. He also discusses Bell's Theorem, Gleason's Theorem and other results. It does not go very deep, but I found it to be an excellent beginner's introduction.
Most papers on quantum mechanics don't explain issues like interpretation clearly and non-locality clearly. The most notable exceptions to this are David Deutsch and to a lesser extent David Wallace.
"The Fabric of Reality" by David Deutsch is a popular book that explains quantum mechanics, see especially chapter 2. See also "The Beginning of Infinity" by Deutsch, Chapters 11 and 12.
If you are willing to do a little matrix algebra you might want to try his lectures on quantum computation:
Deutsch has also written two papers explaining why quantum mechanics is entirely local:
You might think that Bell's theorem implies non-locality but it doesn't. Bell's theorem explains that if you had a theory that describes the world using stochastic variables, then to reproduce Bell type correlations it would have to be non-local. But a quantum mechanical system is described by an algebra of Hermitian operators, not by stochastic variables. So Bell's theorem doesn't imply that quantum mechanics is non-local.
David Wallace also has some papers explaining various issues such as the measurement problem: