  The stellar initial mass function (IMF) describes how many stars form at
which mass. Despite recent observational progress, many fundamental properties
of the IMF are still unknown. Specifically the question, whether starbursts are
biased towards the formation of more massive stars, is controversially
discussed in the literature. This presentation gives an overview of how the
Large Binocular Telescope (LBT) will contribute to answering this question. I
will present (a) the status quo of the IMF research in starbursts, (b) the
importance of direct star counts in nearby templates, (c) the need for
spectroscopy, (d) the advantage of the LBT over its competitors, and (e) what
additional instrumentation I would like to see at the LBT for the proper
investigation of the most massive starforming regions.
