<P>The foundations are thoroughly developed together with the required mathematical background from differential geometry developed in Part III. </P> <P></P> <P>The author also discusses
the tests of general relativity in detail, including binary pulsars, with much space is devoted to the study of compact objects, especially to neutron stars and to the basic laws of black-hole physics. </P>
<P></P> <P>This well-structured text and reference enables readers to easily navigate through the various sections as best matches their backgrounds and perspectives, whether mathematical, physical or
astronomical.</P> <P></P> <P>Very applications oriented, the text includes very recent results, such as the supermassive black-hole in our galaxy and first double pulsar system </P>