The discovery of young globular clusters in merging galaxies and other environments provides an opportunity to study directly the process of globular cluster formation. Empirically it appears that globular cluster formation occurs preferentially in regions in which star formation occurs at a high rate and efficiency. Further, the interstellar medium in such regions is likely to be at a higher pressure than less active star-forming environments. An additional observational clue to the globular cluster formation process is that young globular clusters have little or no mass-radius relationship. In this paper I argue that high pressure and high star-formation efficiency are responsible for current globular cluster formation. I suggest that the precursors to globular clusters are molecular clouds and that the mass-radius relationship exhibited by such clouds is wiped out by a variable star formation efficiency.

13 pages. Review to appear in "Extragalactic Globular Cluster Systems," ed. M. Kissler-Patig, Springer-Verlag