  In these lectures, I review the current status of cosmic strings and cosmic
superstrings. I first discuss topological defects in the context of Grand
Unified Theories, focusing in particular in cosmic strings arising as gauge
theory solitons. I discuss the reconciliation between cosmic strings and
cosmological inflation, I review cosmic string dynamics, cosmic string
thermodynamics and cosmic string gravity, which leads to a number of
interesting observational signatures. I then proceed with the notion of cosmic
superstrings arising at the end of brane inflation, within the context of
brane-world cosmological models inspired from string theory. I discuss the
differences between cosmic superstrings and their solitonic analogues, I review
our current understanding about the evolution of cosmic superstring networks,
and I then briefly describe the variety of observational consequences, which
may help us to get an insight into the stringy description of our Universe.
