For many physicists quantum theory contains strong conceptual difficulties, while for others the apparent conclusions about the reality of our physical world and the ways in which we discover that reality remain philosophically unacceptable.
This book focuses on recent theoretical and experimental developments in the foundations of quantum physics, including topics such as the puzzles and paradoxes which appear when general relativity and quantum mechanics are combined; the emergence of classical properties from quantum mechanics; stochastic electrodynamics; EPR experiments and Bell's Theorem; the consistent histories approach and the problem of datum uniqueness in quantum mechanics; non-local measurements and teleportation of quantum states; quantum non-demolition measurements in optics and matter wave properties observed by neutron, electron and atomic interferometry.
Audience: This volume is intended for graduate students of physics and those interested in the foundations of quantum theory.

1. The subject of our discussions; E. Santos. 2. Measurement of the Schrödinger wave of a single particle; Y. Aharonov, L. Vaidman. 3. The emergence of classical properties from quantum mechanics: New problems from old; L.E. Ballentine. 4. Deformations of space-time symmetries and fundamental scales; A. Ballesteros, et al. 5. Aspects of quantum reality; S. Bergia. 6. Kochen-Specker diagram of the Peres--Mermin example; A. Cabello. 7. Zeropoint waves and quantum particles; A.M. Cetto, L. de la Peña. 8. Results of atom interferometry experiments with potassium; J.F. Clauser. 9. On the uncertainty relations; J.R. Croca. 10. Continuously diagonalized density operator of open systems; L. Diósi. 11. The hazy spacetime of the Károlyházy model of quantum mechanics; A. Frenkel. 12. Can the experiments based on parametric-down conversion disprove Einstein locality? A. Garuccio. 13. Quantum-mechanical histories and the uncertainty principle; J.J. Halliwell. 14. Experiments with coherent electron wave packets; F. Hasselbach. 15. The ontological interpretation of quantum field theory applied in a cosmological context; B.J. Hiley, A.H. Aziz Muft. 16. State vector reduction via spacetime imprecision; F. Károlyházy. 17. Analyses of classical and thermodynamic limits of quantum mechanics and quantum measurements on the basis of nonstandard analysis; T. Kobayashi. 18. A realistic interpretation of lattice gauge theories; M. Lorente. 19. Is there abridge connecting stochastic and quantum electrodynamics? T.W. Marshall. 20. Action-angle variables inherent in quantum dynamics; J. Martínez-Linares. 21. A philosopher struggles to understand quantum theory: Particle creations and wavepacket reduction; N. Maxwell. 22. Consistent histories and the interpretation of quantum mechanics; R. Omnès. 23. Is quantum mechanics a limit cycle theory? L. de la Peña, A.M. Cetto. 24. Realization and characterization of quantum nondemolition measurements in optics; J.Ph. Poizat, et al. 25. Fuzzy sets and infinite-valued Łukasiewicz logic in foundations of quantum mechanics; J. Pykacz. 26. A model of topological quantization of the electromagnetic field; A.F. Rañada. 27. Postselection and squeezing in neutron interferometry and EPR-experiments; H. Rauch. 28. Macroscopic decoherence and classical stochastic gravity; J.L. Sanchez-Gomez. 29. Dynamics and measurement of the absolute phase in macroscopic quantum systems; F. Sols, R.A. Hegstrom. 30. Realistic quantum theory and relativity; E.J. Squires. 31. On the empirical law of epistemology: Physics as an artifact of mathematics; N.A. Tambakis. 32. Search of a first principle for quantum physics; A.C. de la Torre. 33. Decoherence in an isolated macroscopic quantum system: A parameter-free model involving gravity; J. Unturbe. 34. Nonlocal measurements and teleportation of quantum states; L. Vaidman. 35. Quantum noise in optical photon detectors; A. Vidiella-Barranco, E. Santos.