  How is the universe organized on large scales? How did this structure evolve
from the unknown initial conditions of a rather smooth early universe to the
present time? The answers to these questions will shed light on the cosmology
we live in, the amount, composition and distribution of matter in the universe,
the initial spectrum of density fluctuations that gave rise to this structure,
and the formation and evolution of galaxies, clusters of galaxies, and larger
scale structures. To address these fundamental questions, large and accurate
sky surveys are needed---in various wavelengths and to various depths. In this
presentation I review current observational studies of large scale structure,
present the constraints these observations place on cosmological models and on
the amount of dark matter in the universe, and highlight some of the main
unsolved problems in the field of large-scale structure that could be solved
over the next decade with the aid of current and future surveys. I briefly
discuss some of
