The document introduces JSON (JavaScript Object Notation) in the context of MS SQL Server, explaining its structure as name-value pairs and its supported data types. It highlights the JSON support in SQL Server starting from compatibility level 130, detailing various functions such as isjson, json_value, json_query, json_modify, and openjson, each with examples of usage. The document also emphasizes the importance of understanding JSON paths, validation, and additional resources for further learning.