  The Laser Interferometer Space Antenna (LISA) is the first scientific
endeavour to detect and study gravitational waves from space. LISA will survey
the sky for Gravitational Waves in the 0.1 mHz to 1 Hz frequency band which
will enable the study of a vast number of objects ranging from Galactic
binaries and stellar mass black holes in the Milky Way, to distant massive
black-hole mergers and the expansion of the Universe. This definition study
report, or Red Book, presents a summary of the very large body of work that has
been undertaken on the LISA mission over the LISA definition phase.
