  The Laser Interferometer Space Antenna (LISA) has two scientific objectives
of cosmological focus: to probe the expansion rate of the universe, and to
understand stochastic gravitational-wave backgrounds and their implications for
early universe and particle physics, from the MeV to the Planck scale. However,
the range of potential cosmological applications of gravitational wave
observations extends well beyond these two objectives. This publication
presents a summary of the state of the art in LISA cosmology, theory and
methods, and identifies new opportunities to use gravitational wave
observations by LISA to probe the universe.
