This chapter summarizes the time intervals, date and datetime informats, date and datetime formats, and date, time, and datetime functions available in SAS software. The use of these features is explained in Chapter 3: Working with Time Series Data. The material in this chapter is also contained in SAS Language Reference: Concepts and SAS Language Reference: Dictionary. Because these features are useful for work with time series data, documentation of these features is consolidated and repeated here for easy reference.