  In these proceedings we highlight the primary scientific goals and design of
the WEAVE-LOFAR survey, which will use the new WEAVE spectrograph on the 4.2m
William Herschel Telescope to provide the primary source of spectroscopic
information for the LOFAR Surveys Key Science Project. Beginning in 2018,
WEAVE-LOFAR will generate more than 10$^6$ R=5000 365-960 nm spectra of
low-frequency selected radio sources, across three tiers designed to
efficiently sample the redshift-luminosity plane, and produce a data set of
enormous legacy value. The radio frequency selection, combined with the high
multiplex and throughput of the WEAVE spectrograph, make obtaining redshifts in
this way very efficient, and we expect that the redshift success rate will
approach 100 per cent at $z < 1$. This unprecedented spectroscopic sample -
which will be complemented by an integral field component - will be
transformational in key areas, including studying the star formation history of
the Universe, the role of accretion and AGN-driven feedback, properties of the
epoch of reionisation, cosmology, cluster haloes and relics, as well as the
nature of radio galaxies and protoclusters. Each topic will be addressed in
unprecedented detail, and with the most reliable source classifications and
redshift information in existence.
