General relativity is one of the most elegant and fundamental theories of physics, describing the gravitational force with a most awesome precision. When it was first discovered, by Einstein in 1915, the theory appeared to do little more than provide for minute corrections to the older formalism: Newton's law of gravity. Today, more and more stellar systems are discovered, in the far outreaches of the universe, where extreme conditions are suspected to exist that lead to incredibly strong gravitational forces, and where relativistic effects are no longer a tiny perturbation, but they dominate, yielding totally new phenomena. One of these phenomena is gravitational radiation – gravity then acts in a way very similar to what happens with electric and magnetic fields when they oscillate: they form waves that transmit information and energy.

Only the most violent sources emit gravitational waves that can perhaps be detected from the Earth, and this makes investigating such sources interesting. The physics and mathematics of these sources is highly complex.

Maurice van Putten has great expertise in setting up the required physical models and in solving the complicated equations emerging from them. This book explains his methods in dealing with these equations. Not much time is wasted on philosophical questions or fundamental motivations or justifications. The really relevant physical questions are confronted with direct attacks. Of course, we encounter all sorts of difficulties on our way. Here, we ask for practical ways out, rather than indulging on formalities.