“NoSQL” is a term that is frequently used nowadays. But what does “NoSQL” mean, and what kinds of databases does this term include? How are they different (if at all) from object databases? What problems have people experienced with relational databases, which led to the development of NoSQL databases? In this talk, Martin Fowler introduces the history and development of NoSQL databases, and describes the different types of such systems that exist, along with their relative advantages and disadvantages.