Data.table is an R package designed for fast data manipulation and analysis. It provides an enhanced version of data frames, allowing users to perform operations like filtering, aggregating, and joining data efficiently. Its syntax is concise, making it easier to write complex queries with less code. One of the key features of Data.table is its ability to handle large datasets with speed and minimal memory usage. It achieves this through optimized algorithms and in-memory processing. This makes it a popular choice among data scientists and analysts who work with big data in R.