The Cauchy Problem in General Relativity

Gravitational waves were predicted by Einstein in 1916 as wave solutions of the Einstein-Hilbert equations of General Relativity.Indirect experimental evidence of their existence was only obtained in the past 40 years, most famously through observations of the binary pulsar PSR 1913+16.Direct detection of gravitational waves is anticipated later this decade.It will be enabled by interferometric detectors Virgo and LIGO.We begin with a brief theoretical description and the historical background of the search for gravitational waves.We describe techniques used in interferometric detectors.We introduce the likely sources of gravitational waves and the foundations of data analysis.We briefly summarize key results to date and conclude with perspectives on future scientific payoffs.