Data normalization is a process used in database management to organize data efficiently. It involves structuring a database in a way that reduces redundancy and improves data integrity. By breaking down large tables into smaller, related ones, normalization helps ensure that each piece of data is stored only once, making updates and maintenance easier. There are several levels, or "normal forms," in data normalization, each with specific rules. The most common forms include First Normal Form (1NF), Second Normal Form (2NF), and Third Normal Form (3NF). These forms help eliminate duplicate data and establish clear relationships between different data entities.