  Globular clusters are often assumed to be good tracers of major star
formation episodes in their host galaxies. While observations over the past 2
decades have confirmed the presence of young objects with globular cluster-like
properties in many galaxies, it is still not well understood exactly how the
formation efficiency of bound star clusters relative to field stars and their
mass spectrum depend on external factors. The cluster initial mass function
typically appears to be consistent with a power-law with a slope of about -2,
but most attempts to constrain any upper limit on the CIMF have been limited by
size-of-sample effects. However, evidence is starting to accumulate for
possible truncation of the cluster mass function. It is tentatively suggested
that the upper mass limit may currently be at about 10^5 Msun in the Milky Way
disk, while there are indications that it is about 5x10^5 Msun in M51 and about
2x10^6 Msun in the Antennae. Some extreme starbursts (e.g. Arp 220, NGC 7252)
are (or were) able to form clusters as massive as 10^7 Msun. The overall
formation efficiency of star clusters (relative to field stars) in the Galactic
bulge may not have been much different from that in the disk today, but was
probably significantly higher for metal-poor GCs in halos.
