Black Holes and Gravitational Waves

Black hole coalescences are a major source of gravitational waves in the universe. The current status of observations of these will be briefly reviewed, and we then turn to the gravitational waves themselves. The advantages of a particular gauge choice for representing the waves will be argued for, and used to demonstrate some astrophysical consequences relevant to the nearby environment of coalescing black holes, and other sources  of gravitational radiation. A link will also be made to a form of gravitational wave 'memory'.