The dateutil module is a Python library that simplifies the process of working with dates and time stamps, providing functions such as parsing dates from strings in various formats, calculating the difference between two dates, adding or subtracting time from a given date, and more. It's an extension of the datetime module and can be easily installed using pip. The module provides a parse function for parsing dates into desired string formats, a relativedelta function for calculating the difference between two dates, and functions for adding or subtracting time from a given date. These functions make it easier to work with dates and times in various ways, such as handling time series data.