Globular clusters are the oldest objects in the Galaxy whose age may be accurately determined .
As such globular cluster ages provide the best estimate for the age of the universe .
The age of a globular cluster is determined by a comparison between theoretical stellar evolution models and observational data .
Current uncertainties in the stellar models and age dating process are discussed in detail .
The best estimate for the absolute age of the globular clusters is 14.6 \pm 1.7 Gyr .
The one-sided , 95 % confidence limit on the lower age of the universe is 12.2 Gyr .