  This survey is intended to be a fast (and reasonably updated) reference for
the theory of Stallings automata and its applications to the study of subgroups
of the free group, with the main accent on algorithmic aspects. Consequently,
results concerning finitely generated subgroups have greater prominence in the
paper. However, when possible, we try to state the results with more
generality, including the usually overlooked non-(finitely-generated) case.
