The DateTime.pm module aims to provide a complete, correct, and easy to use date/time object implementation. Currently it handles many date calculations, date math (addition and subtraction), and provides convenient methods for retrieving portions of a date/time. This module properly supports the Olson time zone database, meaning that historical time zone information, and more importantly, daylight saving time rules, can be handled transparently, simply by setting the correct time zone. This is done by using the DateTime::TimeZone module.