The MIT License is a short, simple, and permissive software license. It is an open source license used on popular software such as Ruby on Rails, jQuery, and Node.js. The license grants users the liberty to do virtually anything they wish with the software and associated documentation files, including use, copy, modify, merge, publish, distribute, sublicense, and sell copies of the software. It is known for its brevity and clarity, and ensures proper attribution to the original authors while offering maximum freedom for developers.