With the release of Laravel 5.1 the documentation received a huge overhaul. In the process, some of the older documentation is no longer on the Laravel site.
If you are needing to find the documentation on releases 4.1 and previous you can get them directly from the GitHub repo.
All documentation is created with Markdown and browsing it through the repo is pretty easy by going into the branch and hitting
t to bring up GitHub’s quick filter.