  The notion of nowhere dense graph classes was introduced by Ne\v{s}et\v{r}il
and Ossona de Mendez and provides a robust concept of uniform sparseness of
graph classes. Nowhere dense classes generalize many familiar classes of sparse
graphs such as classes that exclude a fixed graph as a minor or topological
minor. They admit several seemingly unrelated natural characterizations that
lead to strong algorithmic applications. In particular, the model-checking
problem for first-order logic is fixed-parameter tractable over these classes.
These notes, prepared for a tutorial at Highlights of Logic, Games and Automata
2019, are a brief introduction to the theory of nowhere denseness, driven by
algorithmic applications.
