It should be no surprise (especially considering the title of this book!) that Trac and Subversion are the key players in our solution, and they provide a good chunk of the functionality that we need. What may come as a surprise is that for the solution to really meet our needs there needs to be a third player—the Apache web server. There is also a fourth part, WebDAV, which we implement via an Apache module, and hence could be considered to have only a supporting role; but we will see later that it does contribute to the overall solution.
Now we know who the four players in our solution are, let's learn a bit more about them before we learn how they fit, and more importantly work, together.