  What is long-baseline optical/IR stellar interferometry? A few years ago,
many astronomers might not have been able to answer that question properly.
This is today hopefully not the case anymore, because mainstream facilities,
such as the VLTI, the Keck-I or the CHARA array, offer now this delicate
technique to an astronomer who wants to observe his favourite object at the
highest angular resolution available. The large teaching effort on what is
interferometry and for what purpose it can be used, together with weak, but
already convincing imaging capabilities, make the technique reaching a ?mature?
state. I will not discuss here the details of the technique, as already many
booklets are now published on the subject, but rather describe what makes
long-baseline stellar interferometry attractive for the field of hot star
astrophysics.
