This document provides an overview of NoSQL databases. It begins with an agenda that covers the history of NoSQL, what NoSQL is, the CAP theorem, types of NoSQL databases like key-value and schema-less models, advantages of NoSQL like scalability and flexibility, and what is given up like joins and ACID transactions. It then discusses Cassandra as an example NoSQL database and its use of the Dynamo model and Thrift API. Statistics are given showing Cassandra's improved performance over MySQL for Facebook's use case. The document was made by students for their class.