  These notes were prepared to accompany a sequence of three lectures at the
conference Winterbraids XI in Dijon, held in December 2021. In them, we provide
an introduction to slice knots and the equivalence relation of concordance. We
explain some connections between slice knots and exotic smooth structures on
$\mathbb{R}^4$. We also introduce filtrations of the knot concordance groups
and satellite operations.
