  The present paper reviews massive star (initial mass smaller than 120 M0) and
very massive star (initial mass larger than 120 M0) evolution. I will focus on
evolutionary facts and questions that may critically affect predictions of
population and spectral synthesis of starburst regions. We discuss the
ever-lasting factor 2 or more uncertainty in the stellar wind mass loss rates.
We may ask ourselves if stellar rotation is one of the keys to understand the
universe, why so many massive stars are binary components and why binaries are
ignored or are considered as the poor cousins by some people? And finally, do
ultra luminous X-ray sources harbor an intermediate mass black hole with a mass
of the order of 1000 M0?
