Line-Intensity mapping (LIM) uses the integrated flux along the line of sight as
tracer of the LSS. Using relatively low-aperture telescopes, it recovers radial information targeting known spectral lines discarding the continuum emission, which makes the experiments
cheaper compared with galaxy surveys. Mapping the intensity fluctuations of an array of lines
from HI 21cm to optical-UV lines offers a unique opportunity to probe redshifts well beyond
the reach of other cosmological observations, access regimes that cannot be explored other-
wise, and exploit the enormous potential of cross-correlations with other measurements. This
promises to deepen our understanding of various questions related to galaxy formation and
evolution, cosmology, and fundamental physics. In this talk I will cover the current status of
LIM, main measurements and the promised potential for the future, with focus on the
next steps that must be taken to bring this technique to full speed for precision cosmology.
