My GR book: “Relativity Gravitation & Cosmology: a Basic Introduction” (Oxford Masters Series in Physics) is an introduction to Einstein’s general theory of relativity for readers with an undergraduate math background, and includes discussion of recent development in cosmology, issues like dark matter, dark energy, and the accelerating universe, etc. I have just completed the second edition, revising most chapters, adding one new chapter on special relativity and one on black holes as well as updating on GR tests, such as the double pulsar system, and latest cosmological data. It should be availabe by January 2010.