The document discusses NoSQL databases and MongoDB. It defines NoSQL, describes different types of NoSQL databases like key-value, document, graph and column-oriented. It then focuses on MongoDB, explaining its advantages like high performance, flexibility and rich queries. It covers MongoDB concepts like collections and documents. It also discusses JSON structure, MongoDB methods for insertion, querying and removal of documents. Finally, it provides examples of when to use MongoDB, such as for unstructured data, high volume read/writes and changing schemas.