ed, Brussel, 2006. English translation: What is Time? What is space?, Di Renzo Editore, Roma, 2006. Magazine articles Lee Smolin, "Atoms in Space and Time", Scientific American, January 2004. Easier introductory, expository or critical works Abhay Ashtekar, "Gravity and the Quantum," e-print available as gr-qc/0410054. John C. Baez and Javier P. Muniain, Gauge Fields, Knots and Quantum Gravity, World Scientific (1994). Carlo Rovelli, "A Dialog on Quantum Gravity," e-print available as hep-th/0310077. More advanced introductory/expository works Carlo Rovelli, Quantum Gravity, Cambridge University Press (2004); draft available online. Thomas Thiemann, "Introduction to Modern Canonical Quantum General Relativity," e-print available as gr-qc/0110034. Abhay Ashtekar, New Perspectives in Canonical Gravity, Bibliopolis (1988). Abhay Ashtekar, Lectures on Non-Perturbative Canonical Gravity, World Scientific (1991). Rodolfo Gambini and Jorge Pullin, Loops, Knots, Gauge Theories and Quantum Gravity, Cambridge University Press (1996). Hermann Nicolai, Kasper Peeters, Marija Zamaklar, "Loop Quantum Gravity: An Outside View," e-print available as hep-th/0501114. "Loop and Spin Foam Quantum Gravity: A Brief Guide for beginners" arXiv:hep-th/0601129 H. Nicolai and K. Peeters. Edward Witten, "Quantum Background Independence In String Theory," e-print available as hep-th/9306122. Conference proceedings John C. Baez (ed.), Knots and Quantum Gravity'' (1993). Loop quantum gravity Loop quantum gravity