DataFrames and Series are fundamental data structures in the Pandas library, widely used for data manipulation and analysis in Python. A DataFrame is a two-dimensional, labeled data structure that resembles a table, with rows and columns, allowing for the storage of various data types. In contrast, a Series is a one-dimensional labeled array, akin to a single column in a DataFrame. Understanding these structures is crucial for effective data handling, as they provide the building blocks for data analysis tasks, enabling users to perform operations such as filtering, aggregation, and visualization efficiently.