Before a request ever hits your Rails application, it winds its way through a series of pieces of Rack middleware. Middleware sets session cookies, writes your logs, and enables the functionality in many gems such as Warden. With Rails or any Rack app, you can easily insert your own custom middleware, allowing you to log, track, redirect, and alter the incoming request before it hits your application. You will leave this talk confident in writing your own custom middleware, better able to troubleshoot gems that rely on middleware and with an understanding of how your Rails app functions.