This document provides an introduction and overview of MongoDB and how to use it. Some key points: - MongoDB is an open-source document database that provides high performance, high availability, and automatic scaling. It uses documents (similar to JSON objects) rather than tables and rows. - Documents are stored in collections without a predefined schema. Fields can be added, modified or deleted at any time. - Common operations include inserting, querying, updating, and removing documents from collections. Queries can use filters, projections, sorting, skips, limits, and regular expressions. - MongoDB is flexible compared to relational databases as schemas are not rigidly defined. It is suitable for high performance applications that need