Formation of high mass stars.

The author briefly reviews the evidence regarding the evolution of the dense interstellar medium into massive stars. Studies of star formation on large scales based on low angular resolution observations tend to lead to ambiguous conclusions regarding such questions as the cloud density dependence of the star formation rate. Observations of individual clouds and cloud cores show evidence of massive clumps that may become stars, disks around young massive stars, progressive star formation, and infall onto the cores that may be left over from the early stages of star formation.